forget national parks and look into national forests for the type of camping you want to do.
Are you trying to stay within certain states?As my father ALWAYS took us on nature family vacations, i have been to quite a few national parks, whether or not i liked it. :)I suggest Zion National Park or Mt. Hood Oregon.Mt. Hood has free camping for as long as you like, in a very woodsy, open area, there s a lake there to fish from (no charge), it s beautiful, there s snow up at the glacier (X amount of miles away). It s real camping though, no bathrooms, etc.Zion is boring cuz there s nothing to do, but it s beautiful and hiking the narrows is the most fun!
Mojave National Preserve. Death Valley National Park. Joshua Tree National Park. Badlands NP. Petrified Forest/Painted Desert NP. Bandelier NM.What part of the country do you want to go to and what time of year?
A lot of the national parks have back-country camping areas. Check the website for each park.
Here s a link to the site:http://www.nps.gov/index.htm