Bear,
Welcome and congrats on the new tt!!!
What did you guys get???
As mentioned, with any 1500/150 tow vehicle (truck or suv), it will usually max/exceed the payload limit before reaching the max tow rating.
Look for the yellow sticker in the drivers door of your 'burb, as well as any possible new truck if you decide to go that route. It states "All occupants and cargo not to exceed: XXXXlbs". That is the rated payload for that vehicle as it rolled off the assembly line, before any accessories have been added. I disagree with Kenzie regarding 150lbs for a driver being in addition to the stated sticker payload. I post this based on the wording of the sticker- "ALL OCCUPANTS...". To me that means any occupant in the vehicle, which includes all of the driver weight.
How much does the whole family weigh, what do you anticipate hauling in the rear of the burb or truck bed (cooler(s), firewood, bikes, etc), what accessories do you think you may add to a truck (step bars, tonneau cover or truck cap/topped, etc)? Add those weights up plus the ~100lbs for the wdh, and see what's left from the yellow sticker as mentioned.
Keep in mind the average rv owner adds about 1000lbs to the "brochure" dry weight if the trailer. So you could be very close to 8000lbs all loaded up for a trip. And with a 12-15% tw, that could be ~ 960lbs-1200lbs tw. For a tt, you generally need 12-15% of the loaded trailer weight to be tw. Obviously this will vary from trailer to trailer, but in a lot of cases having a lower tw can and will result sway which can be very dangerous. While the E4 is a great wdh system, the integrated sway control could mask a light tw issue until it's to late, so still be careful loading!
Speaking of tw, the "brochure" dry tw usually does not include the weight of the propane tanks or a battery on the tongue. That adds ~120lbs for 2-20lb tanks and a battery, or ~160lbs for 2-30lb tanks and a battery before even loading the trailer with anything else.
So to answer the big question, will your burb tow the trailer? Yes, it will. But pending on the family weight, and actual loaded tw, you may be over the payload, and possibly the rear axle rating. Same thing with a 1500 GM Truck, pending the family/cargo/accessories/tw total and what towing options the new truck has.
Do go for the NHT Max Tow package if you stay with a 1500. 5.3 would probably do the job with the NHT option, but the 6.2 would do it better towing cross country. If you go for a 2500HD, gas or diesel will do the job. Just depends on how much you want to spend, and if you like keeping the motor rpms down or don't mind letting the motor rev if needed to make it up inclines. With the gasser you may need to let the motor rev 3k + when towing depending on the terrain.
Good luck!!!