For your initial plan, I'd suggest just drawing a line from the east coast to the west coast and leaving it as a dream before spending months of preparation. Detailed preparation will likely be wasted without experience.

I'd suggest doing small legs of the type of travel you want to do and learn from them. This can be as simple as walking to work and school everyday, even in bad weather. Or it can be learning about one facet of travel, such as cooking all your meals on your camp stove.

Before you plan the time for that epic journey across the country, I'd suggest several of a week or two in order to learn what you don't know.