Without knowing a lot more about you and your experience level, be impossible to give you much specific advice.

With preparation and common sense, you can ride cross country on any route you want. The ACA maps do make planning a tour much simpler, are educational, and might save you as much as they cost by pointing out low cost/free places to overnight.

The most important thing about the bicycle you choose, after mechanical reliability, is how well it fits you. Very important when riding long distances for comfort and endurance. Go to a local bike shop and let them advise you about fit. Nail down your bike size in cm/inches.

The Fx 7.2 is an ok bike for a tour, but $400 for a used one is too much. Do some research on new prices.

Do some camping with cycling appropriate camping gear to figure out what you'll need to take for this tour. Most start out with too much, so with a bit of practice, you can avoid this mistake.

Read all you can here and at www.crazyguyonabike.com, then come back with more specific questions. But, don't get bogged down in too much minutiae.