You've already given yourself the best advice: get off your arse and do it! It's really not that complicated. Set a date. Get the gear. Plan a route (or make it up as you go), choosing the less-traveled roads. Go. You should, however, take a few shorter, shakedown trips before the big one.
Some people like to go into an endeavor like this well planned out. Others like to just let the experience unfold. If you like to prepare, there's plenty of information here in the "How-To" department (http://www.adventurecycling.org/resources/how-to-department/
) on how to train, how much money you need, what gear you should take, how to plan a route, how to find food, water and places to sleep, and how to deal with other common problems on the road. You might also enjoy reading about other people's experiences in the many journals over at CGOAB (https://www.crazyguyonabike.com/
). Both sites are good places to ask questions.