I've been looking at the American Discovery Trail and have hiked about 40 miles of it since this thread started. Very little of it is actually on roads. There are a lot of little local paths it uses that aren't on maps.

The printed directions are very good and can be followed without a map, although a reasonable map to get back on track if misplaced is a good essential.

I got the maps and data points for Missouri, Kansas and Colorado. I rode a bicycle through Missouri pretty much along the same route and it's fine for walking. I think I'd take a bus or something through St. Louis and Kansas City. However, the trail through Kansas City gets very good comments in the journals. I've driven the general route though Kansas many times. I say general as it uses secondary roads in the vicinity of where I drove. No problems I can see there.

I've found Streets and Trips to be the best for planning. It won't give a perfect track, but close enough. I found it's seldom more than 10 miles between grocery stores within 0.3 miles of the trail.

It starts to fall apart a little bit where it uses the Colorado Trail. There are only a few weeks in the year when snow isn't a threat, but it's easy enough to go around on roads. The Colorado Trail is challenging to plan, but a person who walked from Delaware should be able to figure it out with the data book, maps, and monitoring weather through www.trailforums.com.

Personally, if I was set on crossing the country, I'd consider heading north out of Colorado into Utah, Idaho, Montana and Oregon. But that would take a little more planning to see if it's feasible.

Camping isn't a serious problem. I've called a few small town police departments and they all said they'd find a place to spend a night if you are passing through. That agrees with a book I've read about a solo bicycle trip across the country.

Planning it is really a simple process, just not easy as it's so big. I think I'd want a friend planning ahead for me and making calls to police stations for camping. I'd probably use a bounce box to send maps forward and resupplies in case I couldn't find what I wanted. You can generally count on one being someplace in a week. As long as there are always bailout plans, I don't see any extraordinary dangers.

I looked at the Lewis and Clark Trail. Although I like the route better, I couldn't find a databook on it. It looks like it's still in the planning stages.

The whole thing wouldn't be cheap. A very rough estimate is about $11,000. (I've already tripled it.)