Spuds, your plan seems pretty good to me, and probably darn close to what I would do were I in your situation.
A van with a full-size mattress in the back would probably be more my speed than a motorcycle. If I did that, I would only have to check into a hotel probably every 2nd or 3rd night, or maybe forgo the hotels all together and just shower at truck stops as needed. The van would be more comfortable in the rain or cold for sure, and I could always drive with the windows down when the weather was nice.
If, after a few (or five or ten) years of that, I decided that I had seen much of America and wanted to go international, I would strongly consider eschewing the cramped, invasive, and hectic nightmare that is modern commercial air travel in favor of traveling by ship. Of course, there are the commercial cruises (which have lots of entertainment options but tend to be expensive), but a lesser-known option is to book passage aboard a private freighter. I'm told the prices are quite reasonable and the food is very good, but pack lots of books, cards, etc. as you are solely responsible for your own entertainment.