How do the map levels work in your mod? Are they randomized like in the real game, and what happens when you move from one area to another? Does it load a new randomized map?
Terrain maps are static, but with random elements (monster, unique monster, events, treasure chest, etc).
When you complete your (map, zones) you unlock another part and moving on. All your hero / stats / items / questprogress / etc are saving and following you.