I spent maybe 2 weeks of the whole trip camping. A lot of that camping was at a hostel though, usually a dollar or 2 a night. The hostels are so cheap and easy to find that I didn't camp much. Also, it's much harder to stealth camp in CA. The jungle is impenetrable in most places and I don't feel comfortable sleeping behind any building down there. The Lonely Planet payed for itself 100 times over on the trip because it showed were the hostels were.
You may know this already but don't try to figure gasoline as a daily thing. Figure out the total miles of the trip, divide by the MPG of your bike, then multiply by gas price. Gas prices change wildly across borders but if you average it at $3 a gallon it oughta be pretty close.
Border expenses were much higher than I expected. Most were $25-40(that includes insurance) and I went through a whole lotta borders. At a rough guess I'd say I spent around $500 on border fees.
I spent a fortune in Mexico on lodging because I couldn't find hostels and I didn't want to camp just anywhere. Hotels were between $20-30 for a nice place.