D77,
Any of the modern 150/1500 series drivetrains (ecoboost, 5.0, 5.3, 5.7, etc) with a 6spd trans and the proper rear gears are more than enough to tow 7k lbs.... The issue towing with a 150/1500 series truck/ suv is the PAYLOAD of the tv (tow vehicle).
Some manufactures listed "brochure" dry weight does not always inlcude some options, even if they are "mandatory options". The dry tw (tongue weight) of a tt (travel trailer) does not include the propane tanks or battery on the tongue either: this alone adds about 120lbs for 2-20lb tanks and battery, or about 160lbs for 2-30lb tanks and battery. On top of this the average family adds about 1k lbs to the tt. And for a stable, safe tow you want on average 12-15% tw (of the loaded tt). This is why some suggest to use 13% tw based on the gvwr of the tt. Though that trailer seems to have a rather heavy dry tw already, not exactly what I would call an "Aerolite".
I mention this because all passengers, cargo inside the tv (coolers, firewood, toys, bikes, etc), the wdh (weight distribution hitch), AND the tw all add toward the payload of the tv. There is a yellow sticker inside the drivers door jamb of all cars & trucks. It states, "All passengers and cargo not to exceed XXXXlbs". This number should not be exceeded. Keep in mind your kids will only get bigger, and HEAVIER as time goes by.
As for the wdh, spend the money for at least a good, middle of the road system with integrated sway control. The Reese Dual Cam, Reese SC, and Equal-I-Zer 4 way systems are very good for the money!!! The Hensley and Pro Pride are better as I understand (never tow with one), but considerably more money.
Do you think your family will be ready to upgrade trailers in a few years? And will the truck/ suv be a daily driver, and if so, how long of trips on average? I ask because maybe it wouldn't hurt to consider a 2500/250 (or even a 3500/350 because price is almost the same as a 2500/250) series truck as mentioned now, so you have the proper truck/ suv for the bigger tt in a handful of years.
Also consider the cargo capacity of the tt. The last thing you don't want is a trailer with hardly any cargo capacity for the food, drinks, clothes, etc needed for an extended trip
One of the things I took into account when we purchased our new Jayco this past July was the axles under different makes and models. One brand we looked at had about a 9500lb gvwr, but only had 2-4400lb rated axles!!!! They didn't include about 700lbs that is on the tv in the trailer axle capacity. Our Jayco has a 9975lb (something like that) gvwr with 2-5k lb axles... And look at the tires on the trailer as well. Some barely have the weight capacity to cover the weight of the loaded trailer minus the tw. There is a very limited sleection of 14" tires available, with 15" tires having a better selection of different sizes and weight ratings. I would rather have a reserve capaity for the axles and tires than running just about their max rating.
This may be something you wouldn't think about until after buying, but look at the location of the outdoor shower if there is one. Friends bought a new 5ver, never considered the outdoor shower. It is under the awning! Who wants a muddy mess there??? Probably could figure something out though.
As I understand on Forest River products, you can purchase a 2nd yr warranty for $150. While we are very happy with our Jayco, we probably would have looked a little closer at them because of it. Even with the outdoor shower issue, there is some nice features on the Puma we liked. Not sure if Thor Industries (makes Dutchmen) does anything similar....
Good luck shopping!!!