Hi, and Welcome to the Great American Roadtrip Forum.
First thing you should really to do is get yourself some good maps which show you your whole trip,m and the land it traverses. These would be available from AAA (free to members. For a trip of this scope a AAA membership would be well advised. Then you might like to follow the advice in this paragraph:
You have all the cities you would like to visit so you can check what interests you along the routes in between. It's all marked on the maps. Maps are invaluable for planning, and essential when on the road. Never a good idea to rely only on your electronics.Originally Posted by AZBuck
As a couchsurfing member of many years, I have never regarded it as a 'free' night's accommodation. You either do something for your host, or bring them a gift, or perhaps take them out to dinner (my preferred reward). Do something to express your appreciation for your host(s). Having hosted lots and stayed with many as well, it is one of the safest ways to travel. Just make sure you leave a reference for every person you meet, host or stay with.
Since this trip is still some time off, why not use this time to host couchsurfers. It is such a rewarding experience. Or even just show people around your little part of the globe.
As for travelling solo, to my way of thinking it is the best way to travel. You are in control of everything, stop when you see something interesting and many more opportunities to meet the locals - in shops, at rest areas, etc. (Just make sure you leave your gadgets in your pocket and greet those you meet.)
Have a great trip
Lifey