Watson said parks near the state's urban centers are especially popular, because camping can be an inexpensive way for someone to visit a city like San Francisco, where hotels can cost 10 or 20 times the price of a camping spot.

CNN: In a slump, camping comes into vogue

Having a virtual camping community is useful, especially for allaying safety concerns about specific spots, an issue every camper takes seriously.

BBC: Camping through Mexico and Central America