I would go 300 blk pistol (as long as you have a secure space) with sub and super rounds for different uses. Plus, whichever handgun you're more comfortable with (me it's my G19). If you end up with just the handgun carry a decent load-out. Have a safe trip and always be vigilant.
Mission is a simplified term. I usually have a plan and idea of where I'm headed and plan my weapons according to activity and threat level. Urban, outdoor activity, camping, day trip, multi-day trip, etc...
Way too expensive if your that close to kbb. Hard to say but that looks like an easy $5-6k damage. I would only do it if the price is right, good news you're in a strong negotiating point.
I love the idea of this and am really close to pulling the trigger. I am just waiting for one of you electric gurus to perform some tests to make sure it's worth it.