There are several possible approaches to planning your route (other than letting the ACA plan it for you). You could get a copy of all the state maps, study the average daily traffic volumes of each road, check out the quality of pavement and width of the shoulders, etc., and plan a detailed route before you start. This information is all readily available on-line. This is a lot of work, but has a good chance of getting you on great cycling roads, and many people enjoy the planning.
Or, you could plan particular segments where you know there's a great cycling path, and link them together.
Or, you could just plan one or two days ahead at a time as you go, using maps and asking locals.
Different people enjoy different approaches. You'll have to figure out what works for you. Also, search this forum and the CGOAB forum for route planning, and you'll get a lot of different advice on how to do it.
Have a great time! You're headed in the right direction.