What do you want this trip to be? What I would recommend is dependent on that. For you, is it about a fast crossing, enjoying the scenery, meeting the people, something else?
Assuming a fast crossing isn't your primary goal, the Trans America route is awesome. We met mostly friendly, kind, and generous people and saw lots of beautiful scenery. The state parks are generally cheap and very nice most places. In many places you will be able to camp for free in town parks, church yards, and other similar locations. If you use the AC maps they will have lots of free places to stay listed and in most small towns just asking around will turn up others. We only resorted to expensive campgrounds a couple times staying for free at least half the time.
On the TA you will meet other tourists and will be able to camp or ride with them some of the time if you want to.
Interestingly, we found that if you are an experienced camper and use an AC route, not much planning is required. Get your gear together, get the maps, find your way to the starting point and start riding. If you are not an experienced camper then some time spend figuring out what gear you need and how to use it is needed.
I would suggest reading some journals on the Crazy Guy on a Bike site (http://www.crazyguyonabike.com
). I think our 2007 Trans America journal (http://www.crazyguyonabike.com/doc/staehling2007
) is a good one for someone planning their first long distance tour to read since it is the story of three first timers.
Good luck on your trip.