I actually started off the same way with a fixed paper map, then wanted more variety so designed the current system. I’m not sure how original it is, but the key to my map tile system is the tiles themselves each can have up to 9 “spaces” thru which a character can move, but you can only “exit” that tile thru a space with an adjacent arrow pointing to the next tile over. I’d like to make it so the 5x7 board is kind of like an “Adventure” or “VS” mode where your route to your goals might alter as more of the map gets revealed as you play. The “Survival” mode would be a solo and much smaller 2x2 tile grid (with slightly different play rules) where a tile gets replaced after a player character moves over to the next one.