More people are doing what you are talking about, only side note you may not get into many off road locations very well, by the time you buy one that is large enough to live in and hall all the toys plus the boat,

as far as the boat, just cut off the hard plastic wheel on the tounge jack and replace it with a small pnuematic tire, I plan doing the very same thing this summer to my cargo trailer as it gets dropped for hunting in the dirt and it don't roll very well at that point, there is a small tire and wheel place on 4th ave In Seattle that has hundreds of tires, there name escapes me at the moment they are a few blocks south of the stadium on the left, I bought some for a small generatore that needed to be mobile in rough conditions years ago.

Bud.