Just get the gear with the highest damage and defense you can find. You can only wear one Armor and one Weapon, so there's not much complexity there.
There's no post-game, no. When you beat the final boss, the game's over.
There's no classes in CoC1.
All you gotta do is hit Explore a bunch from the main camp until you unlock the Lake, then explore there a bunch. Grinding stats is basically the core mechanic and the Lake and Forest will slowly increase the ones you need to survive early game.
Yeah, as Bubble said, each region is actually some distance away from the last; they aren't meant to be overlaid quite like that. :p Having said that, though, cool stuff!
There's a map of the Frost Marches as a whole (obviously, it's a draft and VERY subject to changes as we go), but not one of...
You need to have lost several times or be a bimbo for that sub-scene. If you've beaten the orcs a bunch of times before, you need to "work off" those wins by losing a bunch. There's a hidden Submission stat that isn't necessarily 1:1 with wins or losses.