You could have a scaled down version of the level that fits into the screen behind the actual level (or is set invisible) but always stays in frame. The pathfinding behavior could work on a single pixel representing a character. Then, calculate the position of the characters according to the position of the pixel. It would be something like a mini map where you calculate the position of a symbol off of the position of the character but in reverse.
Great minds think alike While waiting for a response, I created a minimap with pathfinding! However I created it as an actual visible minimap. Problem is the pathfinding behaviour seems to break down on such a small scale.
My mini dudes are 3x3 (down from 17x17) and I've toyed with cell size of 1, 2, 3.. (down from 16) and with cell border also, but that's back to -1. The space to move is about 7-8 pixels. They just don't seem to go to the centre of my room sprites properly, and sometimes get stuck or whatever. I might make them 1 pixel as you suggest and see if that works.
However.. I could still make an invisible map, as big as my window, and use that. Great idea thanks.
And I will either scale the movement up to my full size map as you suggest, or use some scheme that when the mini guys hit a room sprite, I can use that to trigger something. We'll see.
I'd still be interested in a simple means to "auto navigate a map of numbered rooms using the room number".