National Parks and Federal Recreational Lands Annual Pass: This one pass will get you into all the national parks plus the Federal Recreation areas.
Hot tip: many of these locations are national park worthy, with great camping, minus the people!
Mojave National Preserve - Southeastern California (camping mecca 50 miles from Las Vegas)
Mojave National Preserve Camping Guide
Lake Mead National Recreation Area
Grand Canyon - Parashant National Monument (primitive camping only, campervans OK)
Vermillion Cliffs National Monument
Grand Staircase - Escalante National Monument
Glen Canyon National Recreation Area
Valley of Fire State Park - Overton, NV (55 miles NE of Las Vegas)
Lake Havasu State Park - Arizona
Camping Guide Nevada: Excellent resource guide for public campgrounds in Nevada's Great Basin and the Sierra Nevada of California