Some like short beds, some long. I have a Dodge CC short bed because I like the look and it's a little shorter for us to park. My older FW is 8 1/2 feet wide and flat on the front so I went with a sliding hitch.
A long bed will make hitch shopping much cheaper. There are even cheaper used ones on Craigslist all the time. I have a metal enclosure for my Honda 3000 generator in front of my hitch and it just fit. If you can live with a long bed, get it.
Another important thing to consider is 3/4 or 1 ton. Of course you all ready know what your van can do. If you get a 3/4 and want to stay within the trucks specs you will be shopping for a lighter weight FW. If you want to buy a truck and you dont know what type of FW you will buy, get a one ton. It gives you a lot more pin weight.
My 2013 Silverado 1500 had a payload of 1,650
My sons Dodge 2500CC long bed is 2,130------480 lb over a 1500
My 2014 Dodge 3500 CC SB SRW is 3,840------- 1,710 lb over a 2500