ok the auto driver works but needs work

src/world/Map.lua

@@ -29,6 +29,46 @@ local function hashSet(list, into)
   return into
 end
 
+-- Passability of a cell of an UNLOADED map def -- the connected neighbor
+-- during an edge crossing.  pokered's collision check reads the neighbor
+-- strip's tile bytes, so a step off the map edge onto a solid tile of
+-- the connected map bumps exactly like an in-map wall; the port needs
+-- the same read without building the whole Map.  Same math as cellTile
+-- on the raw blocks, honoring the surf rule (water/shore passable only
+-- while surfing, same fallbacks as Map.new).
+function Map.defPassable(def, tilesetDef, cx, cy, surfing)
+  if not (def and tilesetDef and tilesetDef.blocks and tilesetDef.walkable) then
+    return true -- no data to judge with: keep the old permissive behavior
+  end
+  local tx, ty = cx * 2, cy * 2 + 1
+  local bx, by = math.floor(tx / 4), math.floor(ty / 4)
+  local id
+  if bx < 0 or by < 0 or bx >= def.width or by >= def.height then
+    id = def.borderBlock
+  else
+    id = def.blocks[by * def.width + bx + 1]
+  end
+  local block = tilesetDef.blocks[(id or 0) + 1]
+  if not block then return false end
+  local tile = block[(ty % 4) * 4 + (tx % 4) + 1]
+  for _, t in ipairs(tilesetDef.walkable) do
+    if t == tile then return true end
+  end
+  if surfing then
+    for _, t in ipairs(tilesetDef.waterTiles or WATER_TILES) do
+      if t == tile then return true end
+    end
+    local shore = tilesetDef.shoreTiles
+    if shore == nil and not NO_SHORE_TILESETS[def.tileset] then
+      shore = SHORE_TILES
+    end
+    for _, t in ipairs(shore or {}) do
+      if t == tile then return true end
+    end
+  end
+  return false
+end
+
 function Map.new(def, tilesetDef)
   local self = setmetatable({}, Map)
   self.def = def

src/world/OverworldController.lua

@@ -883,8 +883,7 @@ function OverworldState:checkEdgeExit(dir)
 
   local conn = self.map:connection(COMPASS[dir])
   if conn then
-    self:crossConnection(dir, conn)
-    return true
+    return self:crossConnection(dir, conn)
   end
   return false
 end
@@ -898,7 +897,7 @@ function OverworldState:crossConnection(dir, conn)
   local dest = Game.data.maps[conn.map]
   if not dest then
     Logger.warn("connection to unknown map %s", tostring(conn.map))
-    return
+    return false
   end
   local p = self.player
   local x, y = p.cellX, p.cellY
@@ -914,6 +913,15 @@ function OverworldState:crossConnection(dir, conn)
   end
   x = math.max(0, math.min(destW - 1, x))
   y = math.max(0, math.min(destH - 1, y))
+  -- pokered's collision check reads the NEIGHBOR strip's tile bytes, so
+  -- stepping off the edge onto a solid tile of the connected map bumps
+  -- exactly like an in-map wall. Without this read, Pallet's south
+  -- shore (land at x2-3) walked straight onto ROUTE_21 (3,0) -- a
+  -- collision tile -- stranding the player on a cell no walk can leave.
+  if not Map.defPassable(dest, Game.data.tilesets[dest.tileset], x, y,
+                         p.surfing) then
+    return false
+  end
   self:setMap(conn.map, x, y, p.facing, { seamless = true })
   -- place the player one cell before the seam (their old world spot,
   -- which the neighbor strip renders identically) and start the step
@@ -931,6 +939,7 @@ function OverworldState:crossConnection(dir, conn)
   p.stepFramesCur = Game.save.onBike
     and (FieldDefaults.world(Game.data, "bikeStepFrames") or 8)
     or (FieldDefaults.world(Game.data, "stepFrames") or 16)
+  return true
 end
 
 -- -------------------------------------------------------------------------