V8 or V6 doesn’t matter…as long as it has enough torque and hp.
3500 lbs dry then add in all the other weight and it could easily bring you up to 5000lbs. That’s a Class III. If you’re going to do a LOT of towing then get a vehicle that’s Class IV. Otherwise any good Class III rated vehicle will do. When you get into a Class IV rated there are very few if any V6’s out there. You’ll probably have to go to a V8.
If in the Class III range vehicle…Any mid-size SUV (RWD) will be fine. 4runner, Pathfinder, Explorer will be fine.
For Class IV…Nissan Armada, Toyota Sequoia, Ford Explorer (with the V8). These vehicles are smaller then the Suburban, but can still tow a LOT.
One last thing…
You made the following statement…
"The trailer is 17’, and weighs about 3,500 lbs. empty. With water and sundries we’re talking about 4,500 lbs "
YOU NEVER EVER TOW WITH WATER OR WASTE. Maybe up to 10 gallons would be fine…but NEVER a tank full…You’re asking for trouble if you do.