a.k.a. The Shire
I'm new to this game but I think I can answer your questions:
1. No, the Adventure treasure cards are only used when the scenario briefing mentions them.
2. You cannot move onto a tile that hasn't been laid yet because unless you END your movement on an unexplored edge, a tile doesn't get placed at that time.
More precisely, you have to end your Hero Phase on an unexplored edge. So you can't move onto the new tile. It means the monster always get first bash at you (as you stand there peering into the gloom and wishing you'd brought a torch and your specs).