Since you still have time I'll suggest;
Look at some travel trailers, for a single guy a 25' unit can be comfortable. The TT also allows you to unhitch and go exploring without dragging the house along.
You will want to do stuff, be it an atv, bike, scooter or whatever, the truck will give you carry space, a Toyhauler will as well.
You commented on having a kayak and maybe a scooter. A small scooter 150cc will fit in a 6.5' truck bed. if you want a larger bike, dirt or street, you'll need an 8' bed.
If you are looking at boondocking pay attention to tank sizes. Water becomes your biggest/heaviest item be it fresh or waste. Black tanks go a long way, but fresh and grey usage adds up quickly. Its not too hard to carry extra water into an area, but if you cant dump grey that can be a problem.
If you are going to use Campgrounds, Famcamps or otherwise, use them for the times you want full hookups, 120VAC, water usage for a long shower, and for doing things (laundry, maintenance, etc) then go back out and dissappear for a couple of weeks.
Dont try to run nonstop, moving to a new location is a large expense. Travel shorter distances and soak up the local area, If you're retired, you arent supposed to be in a rush.
