Think of it this way, 1500 Suburban is roughly equal to a 1500 short bed pickup with about 800 pounds of added sheet metal and seats. That reduces the pickups real payload from maybe 1200 pounds to 4-500 pounds. Subtract weight of all the bodies you plan to carry, even consertatively at 400 pounds, and your available payload for hitch is...... wait for it..... nothing!
There are tons of E250/350 passanger vans out there, you just need to search a little. Check Ebay for starters.
OH and forget those wonderful dry or shipping weights everybody loves to throw at you. No one has ever gone camping with a completely empty trailer. Instead to be on the safe side, look at GVWR trailer numbers, and use 12% of the GVWR as tongue weight. May not be perfect, but a happy surprise is sure better than a sad one.