So I've been doing some more planning on the story side of things and this is what I have so far.

You guys (the PCs) have been hired by a local lord to go into an old world ruin with current ideas for the actual ruin in question include:
- A subway/metro system underground
- A Walmart in the middle of no where
- An airport
- A shopping mall

I'm planning for the actual RP to go something like:
1. The gathering (the part where everyone meets up at the tavern or something similar where you get the quest)
2. The travel (actually getting to the ruin takes time and will involve outdoorsy survival stuff, likely take two days or more)
3. The ruins (doing the fighting and searching and avoiding traps)
4. The way back and the reward (gotta haul it back to cash in your loot before going your separate ways)

As for the actual gathering reason, one could just be the simple tavern rumor leads to a crew going out for the treasure. Another slightly more complex is that all of you have actually been arrested by a local lord and told if you go find this old world artifact you'll be free of your charges. In both cases, there would be an NPC accompanying you either as a sort of local guide or as a warden to make sure you don't just run off.

Thoughts or ideas?