LeAndra,
You're right. I get a lot of great ideas from Family Fun magazine. I usually just google "exchange rate" and then the coin amount and something will turn up. Not very scientific or organized

Regarding your travels, have you seen this website?
http://www.cross-country-trips.com/ It chronicles the journeys of a family who traveled with 2 boys over the summers just like you. She gives lots of information...great resource!
So glad to have you with us.
Jennifer