Does anyone have any ideas for getting larger diameter high flotation tires on a small boat trailer?

I was dropping one of my boats in to a few remote lakes last week and was thinking there should be a better way...

What comes to mind are the big balloon tires on beach carts/trailers. Though, I need something that can go down the road (trails and asphalt).

Some snowmobile trailers have what appear to be golf cart wheels/tires. Those are more than twice as wide as what the trailer I was using have. I think I need something bigger and more of a balloon. Some of the knobby ATV tires are getting closer, but they still are smaller diameter tires than what I am imagining. The beach tire types may be too much of a "balloon" - they surely don't look like they can go down the road.

What I'm after is to keep the trailer axle out of the muck and be able to back it over soft marshy shorelines. One place I dropped in was that at the waters' edge combined with larger rocks (canadian shield rock, not great lakes rocky beach) going down to the lake. I dragged the frame over the rocks.

 

Could you use a wider passenger car tire? I know some of the fancy wake boats come with wide low profile tires, and I'm sure they do it for looks only, but . . . . . What bolt pattern is your trailer, and current wheel and tire size?

 

What size tires are on the trailer now? I'd look at a wide light truck tire, if it is a 15" rim on it. My reasoning for light truck tire is a stiffer sidewall.