I use a variety of resources when planning a dirt road adventure. National Forest and National Park maps, published books and the internet are my primary tools. The following books are the back bone of my library. Backcountry Adventures by Peter Massey and 3 books by Tony Huegel, California Coastal Byways, California Desert Byways and Sierra Nevada Byways. I use an inexpensive Magellan GPS system and it's associated map software with an inexpensive old lap top PC - to take into the field in case we need to re plan our routes. Books are a great starting point, but keep in mind that the data on them can be dated even before they are published. Roads are added and or removed and road conditions constantly change. So it doesn't hurt to ferret out data from the internet or National Forest ranger stations. Good luck and as a good Boy Scout will tell you - Be Prepared.