We have a 2000 mile round trip planned for February (DC area to Tampa to Charleston to DC). I am only 32 and still have young kids, mortgage, etc to worry about. At 10mpg I have to buy 200 gallons of gas (at $3.50) just to make the trip. Thats $700 in gas. If I got 12 or 13mpg, thats 154 gallons or $539. That extra $160 would buy a lot of diapers for the baby. That being said, I knew that it would be expensive to camp and made the decision to buy a truck and camper anyways. I won't let it STOP me, but it certainly has slowed me down.
Does it affect how I camp? Yes it does. I would love to take MORE longer trips and see this beautiful country with my young kids. With the higher cost of fuel and the reality that its hard to get good mileage, it limits my ability to travel more.
When I am older and retired, I hope to be in good enough shape to take more and longer trips. I hope the longer trips, with more time stopped in between driving, will lessen the blow of high (and rising!!!) fuel costs.