Not sure if we're still talking costs of travel and camping, but I camped throughout Baja, Mexico, Belize, and Guatemala, and Copper canyon without a single issue. Never was I interrupted at night except once I had a nice visitor in the morning. He was just curious what I was doing because I was way the hell off the beaten path where travelers are pretty much non-existant. This was just north of Guatemala in the mountains with the coffee farmers. Because my Spanish sucks I simply waved, wished him a good morning, and smiled. He looked at my me, my tent, and my bike and then left with a smile.
99% of the Mexican I met were excited and thrilled for me to be visiting and exploring their country. They really are a very good group of people. More then I can say about other countries. . .
Costs were around 20-45$ a day, 10 or more of that was spent on gas (I get around 50MPG on my XR650R). Copper Canyon and Baja are slightly more expensive then other areas. Still cheaper then the states (especially hotels, etc).
Tires aren't cheap in Mexico. Put on a fresh tire before you go. I paid 150 for a Pirreli MT21 in Puerto Vallarta. I saw the same tire for around 100$ though in Guatemala (a few days AFTER I finally installed the MT21 I was carrying around in Tikal... grr). I had the border guards and police laughing at my bald Desert IT even. Once again, good group of people.