A 2500HD is really no "bigger" than a 1500 as far as driving and parking. I recommend a F-250 or 2500 series pickup in whatever seating arrangement you need/prefer. One of these will tow almost any travel trailer on the market. It can tow a small to moderately sized fifth wheel. It can haul a small to moderately sized truck camper and pull a boat trailer at the same time. Talk about versatility. Of course, if you are sure that you will never want anything more than a 6,000 pound trailer then you can stick to a lighter duty tow vehicle. I trade often and it gets expensive to upgrade both tow vehicle and trailer at the same time.