For anyone who's interested:
I sent my customer list to a list cleanup service (I use Melissa Data it's $2.95/1K records min $50/list) which I do once a year anyway to get change of address data and avoid wasting money on mailings. It keeps my list clean which makes it infinitely more valuable if I ever sell the business.
Once I updated all of that info and exported it from PCRT to Mailchimp, I created a segment of anyone not in my state (we're smack in the middle of the state, so that works well for us) who had not opened any of the last 5 campaigns. I found just over 500 emails that are most likely useless to me, and cleaned them from my list.
If you live in a giant state, or on the border of a few states, you can find websites that will generate a list of all the zipcodes in a specified radius, and then using some advanced Excel skills create a list of anyone outside of that radius. I grabbed everyone more than 50 miles away, cross referenced it like above, and managed to clean another 60ish addresses. That's more work than I'm willing to do on a regular basis though, so in the future I'll probably stick to sorting by state only. I was curious how big of a difference it would make.