diff --git a/src/doomstat.h b/src/doomstat.h
index e230d0e26..ae0e53fce 100644
--- a/src/doomstat.h
+++ b/src/doomstat.h
@@ -284,7 +284,7 @@ struct textprompt_t
 extern textprompt_t *textprompts[MAX_PROMPTS];
 
 // For the Custom Exit linedef.
-extern INT16 nextmapoverride;
+extern UINT16 nextmapoverride;
 extern UINT8 skipstats;
 
 // Fun extra stuff
diff --git a/src/f_finale.c b/src/f_finale.c
index bd741d8fb..37fb18f47 100644
--- a/src/f_finale.c
+++ b/src/f_finale.c
@@ -1740,7 +1740,7 @@ void F_TitleScreenTicker(boolean run)
 		// prevent console spam if failed
 		demoIdleLeft = demoIdleTime;
 
-		mapnum = G_RandMap(TOL_RACE, -2, 2, 0, NULL);
+		mapnum = G_RandMap(TOL_RACE, UINT16_MAX, 2, 0, NULL);
 		if (mapnum == 0) // gotta have ONE
 		{
 			return;
diff --git a/src/g_game.c b/src/g_game.c
index 8b01b5597..c1df23ec1 100644
--- a/src/g_game.c
+++ b/src/g_game.c
@@ -179,7 +179,7 @@ boolean exitfadestarted = false;
 cutscene_t *cutscenes[128] = {};
 textprompt_t *textprompts[MAX_PROMPTS];
 
-INT16 nextmapoverride;
+UINT16 nextmapoverride;
 UINT8 skipstats;
 
 struct quake quake = {};
@@ -4619,7 +4619,7 @@ static INT32 TOLMaps(UINT8 pgametype)
   *         has those flags.
   * \author Graue <graue@oceanbase.org>
   */
-INT16 G_RandMap(UINT32 tolflags, INT16 pprevmap, UINT8 ignorebuffer, UINT8 maphell, INT16 *extbuffer)
+UINT16 G_RandMap(UINT32 tolflags, UINT16 pprevmap, UINT8 ignorebuffer, UINT8 maphell, INT16 *extbuffer)
 {
 	UINT32 numokmaps = 0;
 	INT16 ix, bufx;
@@ -4663,7 +4663,7 @@ tryagain:
 			|| (usehellmaps != (mapheaderinfo[ix]->menuflags & LF2_HIDEINMENU))) // this is bad
 			continue; //isokmap = false;
 
-		if (pprevmap == -2)  // title demo hack
+		if (pprevmap == UINT16_MAX)  // title demo hack
 		{
 			// vres GHOST_%u
 			virtres_t *vRes;
@@ -4998,17 +4998,65 @@ void G_GetNextMap(void)
 		return;
 	}
 
-	deferencoremode = (cv_kartencore.value == 1);
-	forceresetplayers = forcespecialstage = false;
+	if (grandprixinfo.gp)
+	{
+		// Inherit from GP
+		deferencoremode = grandprixinfo.encore;
+	}
+	else if (K_CanChangeRules(true))
+	{
+		// Use cvar
+		deferencoremode = (cv_kartencore.value == 1);
+	}
+	else
+	{
+		// Inherit from current state
+		deferencoremode = encoremode;
+	}
 
-	UINT16 newmap, curmap = gamestate == GS_LEVEL ? gamemap-1 : prevmap;
+	forceresetplayers = forcespecialstage = false;
 
 	// go to next level
 	// nextmap is 0-based, unlike gamemap
 	if (nextmapoverride != 0)
 	{
-		newmap = (UINT16)(nextmapoverride-1);
+		nextmap = (nextmapoverride-1);
 		setalready = true;
+
+		if (nextmap < nummapheaders && mapheaderinfo[nextmap])
+		{
+			if ((mapheaderinfo[nextmap]->typeoflevel & G_TOLFlag(gametype)) == 0)
+			{
+				INT32 lastgametype = gametype;
+				INT32 newgametype = G_GuessGametypeByTOL(mapheaderinfo[nextmap]->typeoflevel);
+				if (newgametype == -1)
+					newgametype = GT_RACE; // sensible default
+
+				G_SetGametype(newgametype);
+				D_GameTypeChanged(lastgametype);
+			}
+
+			// Roundqueue integration: Override the current entry!
+			if (roundqueue.position > 0
+				&& roundqueue.position <= roundqueue.size)
+			{
+				UINT8 entry = roundqueue.position-1;
+
+				/*if (grandprixinfo.gp)
+				{
+					K_RejiggerGPRankData(
+						&grandprixinfo.rank,
+						roundqueue.entries[entry].mapnum,
+						roundqueue.entries[entry].gametype,
+						nextmap,
+						gametype);
+				}*/
+
+				roundqueue.entries[entry].mapnum = nextmap;
+				roundqueue.entries[entry].gametype = gametype;
+				//roundqueue.entries[entry].overridden = true;
+			}
+		}
 	}
 	else if (roundqueue.size > 0)
 	{
@@ -5027,6 +5075,7 @@ void G_GetNextMap(void)
 
 		while (roundqueue.position < roundqueue.size
 			&& (roundqueue.entries[roundqueue.position].mapnum >= nummapheaders
+			|| mapheaderinfo[roundqueue.entries[roundqueue.position].mapnum] == NULL
 			|| (permitrank == false && roundqueue.entries[roundqueue.position].rankrestricted == true)))
 		{
 			// Skip all restricted queue entries.
@@ -5047,6 +5096,9 @@ void G_GetNextMap(void)
 				D_GameTypeChanged(lastgametype);
 			}
 
+			// Is this special..?
+			forcespecialstage = roundqueue.entries[roundqueue.position].rankrestricted;
+
 			// On entering roundqueue mode, kill the non-PWR between-round scores.
 			// This makes it viable as a future tournament mode base.
 			if (roundqueue.position == 0)
@@ -5056,7 +5108,7 @@ void G_GetNextMap(void)
 
 			// Handle primary queue position update.
 			roundqueue.position++;
-			if (grandprixinfo.gp == false || gametype == roundqueue.entries[0].gametype)
+			if (grandprixinfo.gp == false || gametype == GT_RACE) // roundqueue.entries[0].gametype
 			{
 				roundqueue.roundnum++;
 			}
@@ -5168,24 +5220,28 @@ void G_GetNextMap(void)
 		else
 		{
 			cm = prevmap;
-			if (++cm >= nummapheaders)
-				cm = 0;
 
-			while (cm != prevmap)
+			do
 			{
+				if (++cm >= nummapheaders)
+					cm = 0;
+
 				if (!mapheaderinfo[cm]
 					|| mapheaderinfo[cm]->lumpnum == LUMPERROR
 					|| !(mapheaderinfo[cm]->typeoflevel & tolflag)
-					|| (mapheaderinfo[cm]->menuflags & LF2_HIDEINMENU)
-					|| M_MapLocked(cm+1))
+					|| (mapheaderinfo[cm]->menuflags & LF2_HIDEINMENU))
 				{
-					if (++cm >= nummapheaders)
-						cm = 0;
+					continue;
+				}
+
+				if (M_MapLocked(cm + 1) == true)
+				{
+					// We haven't earned this one.
 					continue;
 				}
 
 				break;
-			}
+			} while (cm != prevmap);
 
 			nextmap = cm;
 		}
@@ -5230,13 +5286,13 @@ void G_GetNextMap(void)
 	}
 
 	// We are committed to this map now.
-	if (newmap == NEXTMAP_INVALID || (newmap < NEXTMAP_SPECIAL && (newmap >= nummapheaders || !mapheaderinfo[newmap] || mapheaderinfo[newmap]->lumpnum == LUMPERROR)))
-		I_Error("G_GetNextMap: Internal map ID %d not found (nummapheaders = %d)\n", newmap, nummapheaders);
+	if (nextmap == NEXTMAP_INVALID || (nextmap < NEXTMAP_SPECIAL && (nextmap >= nummapheaders || !mapheaderinfo[nextmap] || mapheaderinfo[nextmap]->lumpnum == LUMPERROR)))
+		I_Error("G_GetNextMap: Internal map ID %d not found (nummapheaders = %d)\n", nextmap, nummapheaders);
 
 #if 0 // This is a surprise tool that will help us later.
 	if (!spec)
 #endif //#if 0
-		lastmap = newmap;
+		lastmap = nextmap;
 }
 
 //
@@ -5300,7 +5356,7 @@ static void G_DoCompleted(void)
 
 	S_StopSounds();
 
-	prevmap = (INT16)(gamemap-1);
+	prevmap = (UINT16)(gamemap-1);
 
 	if (!demo.playback)
 	{
@@ -6574,8 +6630,14 @@ UINT16 G_FindMapByNameOrCode(const char *mapname, char **realmapnamep)
 			return gamemap;
 		else if (mapname[0] == '+') // next map
 		{
+			//TODO: FIXME
+			// THIS CURRENTLY ALWAYS RETURNS ZERO. FIGURE OUT WHY.
 			G_GetNextMap();
-			return nextmap;
+
+			if (nextmap < NEXTMAP_INVALID)
+				return nextmap;
+			else
+				return 0;
 		}
 
 	}
diff --git a/src/g_game.h b/src/g_game.h
index 0635ccfea..2e2f257ae 100644
--- a/src/g_game.h
+++ b/src/g_game.h
@@ -397,7 +397,7 @@ FUNCMATH INT32 G_TicsToMilliseconds(tic_t tics);
 UINT32 G_TOLFlag(INT32 pgametype);
 INT16 G_GetFirstMapOfGametype(UINT8 pgametype);
 
-INT16 G_RandMap(UINT32 tolflags, INT16 pprevmap, UINT8 ignorebuffer, UINT8 maphell, INT16 *extbuffer);
+UINT16 G_RandMap(UINT32 tolflags, UINT16 pprevmap, UINT8 ignorebuffer, UINT8 maphell, INT16 *extbuffer);
 void G_AddMapToBuffer(UINT16 map);
 
 typedef struct 
diff --git a/src/lua_baselib.c b/src/lua_baselib.c
index 78ac9d208..1cb9f7202 100644
--- a/src/lua_baselib.c
+++ b/src/lua_baselib.c
@@ -3519,7 +3519,7 @@ static int lib_gSetCustomExitVars(lua_State *L)
 
 	if (n >= 1)
 	{
-		nextmapoverride = (INT16)luaL_optinteger(L, 1, 0);
+		nextmapoverride = (UINT16)luaL_optinteger(L, 1, 0);
 		skipstats = (INT16)luaL_optinteger(L, 2, 0);
 		if (lua_compatmode && nextmapoverride)
 			nextmapoverride = G_KartMapToNative(nextmapoverride);
diff --git a/src/m_menu.c b/src/m_menu.c
index 2a9f3bb7a..473529cb4 100644
--- a/src/m_menu.c
+++ b/src/m_menu.c
@@ -2747,7 +2747,7 @@ static INT32 M_DrawMenuItem(menuitem_t *item, INT16 x, INT16 y, INT32 vflags, bo
 		case ITF_THUMBNAIL:
 		{
 			UINT16 mapnum = G_MapNumber(item->patch);
-			scale = M_GetMapThumbnail(mapnum < nummapheaders ? mapnum : -1, &p)/4;
+			scale = M_GetMapThumbnail(mapnum < nummapheaders ? mapnum : NEXTMAP_INVALID, &p)/4;
 			break;
 		}
 		case ITF_PATCH:
@@ -3698,7 +3698,7 @@ static void M_DrawLevelPlatterMap(const levelselectmap_t *lsmap, INT32 x, INT32
 	// wide thumbnails? mmm... i dunno... maybe...
 	patch_t *patch;
 	boolean encore = cv_kartencore.value == 1 && levellistmode == LLM_CREATESERVER && cv_newgametype.value == GT_RACE;
-	fixed_t thumbscale = M_GetMapThumbnail(lsmap->available ? lsmap->mapnum : -1, &patch);
+	fixed_t thumbscale = M_GetMapThumbnail(lsmap->available ? lsmap->mapnum : NEXTMAP_INVALID, &patch);
 	thumbscale = FixedMul(thumbscale/4, scale);
 
 	V_DrawSciencePatch(x*FRACUNIT - patch->width*thumbscale/2 + (encore ? patch->width*thumbscale : 0),
diff --git a/src/p_spec.c b/src/p_spec.c
index 995308fd1..d3d02dd29 100644
--- a/src/p_spec.c
+++ b/src/p_spec.c
@@ -5286,7 +5286,7 @@ static void P_ProcessExitSector(player_t *player, mtag_t sectag)
 		return;
 	}
 
-	nextmapoverride = (INT16)(udmf ? lines[lineindex].args[0] : lines[lineindex].frontsector->floorheight>>FRACBITS);
+	nextmapoverride = (UINT16)(udmf ? lines[lineindex].args[0] : lines[lineindex].frontsector->floorheight>>FRACBITS);
 
 	if (lines[lineindex].args[1] & TMEF_SKIPTALLY)
 		skipstats = 1;