Re: Pickup / Camper / Boat
My Dad had a pickup camper. Both pop-up and a big "hang over the bed 3 ft" model with full kitchen, full shower/head and two full double beds. All on a pickup. Towing a fully loaded utility trailer (wxlxh = 8x10x6) with gally and storage weighing in (my guess) around 1000 lbs fully loaded with water, food, bottled gas, tents, and all the camping gear (it was a rolling kitchen with storage). That is what we needed for a family of 6.
My Dad spent a lot of time choosing what truck to order new. That was a real big deal at the time. He ordered the one ton with posi and granny trans because that was rated to haul his combo setup. Total towing package (trailer and camper) must have been well over 3500 lbs.
The truck was a 1 ton 1975 Chevy pickup with "granny trans" and 350 4 barrel 2 wheel drive. NOT dual rear wheels, but with posi. And it had anchors on the exterior sides of fleet-side bed to anchor the camper to (with turnbuckels in the middle, to tighten the whole thing down)
That combo when through everything except soft deep sand. And it was a bit tippy. Dad always slowed down on sharp turns. The granny trans pulled the rig out of some steep, dark, unpaved camp grounds. We spent lots of time at the outer banks (before all the developemnt) in NC and drove over sand or gravel roads to pull the rig near spitting distance of the water.
That truck hauled that stuff up and down the east coast from NJ to GA over and over again for years cruising at a steady 65 on the highway at a whopping 11 mpg.
If I remember correctly, that 350 was only rated 180 hp at the time. Could be wrong.
The truck later pulled a 28 ft 5th wheel camper with no problems at all.
My point is a 350 v8 will probably do you just fine with the appropriate engine cooling (and auto transmission cooling if you go auto) and rear axle ratio. Think 3.7 or higher numeric rear.
Remember: towing is towing is towing. Righ hp, right gear ratio, right cooling, right alternator, right spring capcity and it will do what you want. Too big and it will become a big expense.
Have fun!