When you know exactly where you are going, use the BLM website to plot your course. For example, here's the route you would take when you want to go to Tuscon, Arizona:
From the BLM home page directory (http://www.blm.gov/nhp/directory/index.htmI) click on the Arizona link which takes you to the Arizona page (http://azwww.az.blm.gov/). Then click on Outdoor Recreation. Choose Tuscon and then click on Camping. Here's what you will find on camping on BLM land in Tuscon:
" Most of the lands managed by the Tucson Field Office contain diverse landscapes without developed campsites, signs or facilities. Camping on public lands away from developed recreation facilities is referred to as "dispersed camping." Most of the remainder of public lands in Arizona are open to dispersed camping, as long as such use does not conflict with other authorized uses or occurs in areas posted "closed to camping," or in some way adversely affects wildlife species or natural resources.
Dispersed camping is allowed on Public Lands in Arizona for no more than a period of 14 days within any period of 28 consecutive days. The 28-day period begins when a camper initially occupies a specific location on public lands. The 14 day limit may be reached either through a number of separate visits or through 14 days of continuous overnight occupation during the 28 day period. After the 14th day of occupation, the camper must move outside of a 25 mile radius of the previous location until the 29th day since the initial occupation. The purpose of this special rule is to prevent damage to sensitive resources caused by continual use of any particular areas. In addition, campers must not leave any personal property unattended for more than 10 days. To further protect your public lands, campers must not dispose of any refuse, hazardous materials, sewage, or gray water, in any manner pollute the surrounding area. PACK IT OUT. "
This route will work with other cities and other states and we recommend this website highly.