Hi,
Like many have stated, the longbed will ride smoother, have more space, so that the trailer is not trying to come in the back window, and have room for cargo too. It might also have a larger fuel tank.
What to be very careful about (I hear this question a dozen times a month) is do not buy a 2500 pickup for towing a fifth wheel. "The dealer said it would tow anything" is something that I hear time and again! Sure it is 'rated' to tow a 15,000 pound fifth wheel, but the cargo rating might be 1985 pounds, or enough for 20% of the hitch weight on a 7,500 pound fifth wheel.
The hitch weight will be around 150 pounds. You know what the passenger weights will be. IT all adds up quickly, and if you are looking at moderate light 12,000 pound fifth wheel with a 20% hitch weight, that is 2,400 pounds!
So look at the fifth wheels first, and then decide on a pickup. If you fall in love with a Montana fifth wheel, and it happens to be 31' long, with a 14,000 GVWR and 2,000 'dry pin weight' you do not want to already own a pickup with a 2,500 pound cargo rating. You will need to install a 150 pound hitch, and carry 2-3 people, so figure about 500 pounds in the cab, 150 hitch, 2,000 pin weight, that is 2,650 pounds! Add to this any options you might select with the pickup, like 4 wheel drive (about 500 additional pounds that the dealership did not tell you about) crewcab models are around 400 - 500 pounds more than a regular cab.
Get a towing guide for whatever pickups you are looking at. On the Ford towing guide, you can look at 'slide in camper max weight ratings' and get an idea of what a SRW F-350 can carry, VS a F-250 or dually F-350 pickup. Max camper weight is pretty close to your max cargo rating.
In 2005, Ford really stepped up to the plate with some heavy duty pickups. While a 2004 F-250 supercab would have a 7,000 pound base weight with 4X4 and diesel engine, it only had a 8,800 GVWR, crewcab was even heavier curb weight, so less cargo capacity. In 2005 and later models, most F-250's have a 10,000 GVWR, while the SRW F-350 was 11,500 or so, and DRW F-350 could carry as much as 5,500 pounds!
GMC and Dodge caught up a few years later. I can recall a friend with a dually work truck, it was a 1985 Dodge with 10,500 GVWR, and it would wallow around corners, as my buddy put it.
God luck, and happy fifth wheel shopping!
Fred.
