A pickup and camper setup offers the most comfort and flexibility for towing a boat. You cannot tow a travel trailer and then tow a boat behind that. You can buy a full sized Motorhome and tow behind that but then you have no car when you get there so every time you do anything you have to drive the motorhome - not too practical. Obviously you cannot tow BOTH a boat and a car, not in most states.
And imagine backing a boat down a narrow boat ramp with a monster motorhome! And even if you are a real pro and can manage this, imagine your wheels start slipping and sliding on the slippery launch ramp. Not a position I wanted to find myself in.
There is the motorhome "toy hauler" approach where you can load a small car in the back and the space converts to a very rudimentary camping setup. With that you can still tow a big boat, but then you have to also buy the small car and you have a giant and expensive motor home which can end up sitting around with the running gear decaying a good part of the year. Impractical for us in these early stages of our travels.
I gave it a lot of thought. The truck camper was the most flexible option... you just jack up the camper wherever you are, use it on jacks and have the pickup to launch and pull out the boat and drive around the area... or store it and use as the second car at home the rest of the year. Just some of the advantages of a truck camper.