Been a while since I played my AA50 game……
What I used was plastic grooved strips for the edge of paneling or wall board from Home Depot (very inexpensive). You can just use them across the top and bottom of the map to keep it together better.
For my g40 game I built a custom table that the map fit into (so it can’t move). I retrofitted an old pool table so the map it inset about 4 inches below the rails. Over the rails is felt covered plywood that is used for unit cases and dice rolling etc…