Weight & Length Considerations

My TT listed dry TW at 480 pounds and overall weight at 5180 pounds. I have never weighted it, but it tows well without WD. With so much storage in front of the axles, I expect I have added 300-350 pounds of TW. I would not worry about the Grand Design.

The 8500lb TT with a 792 TW will sway like anything you need to load this trailer so you get about 12-13% tongue weight. Other than that buy enough truck to get enough CC Capacity in the bed.

The hitch weight of 792lbs on the Grand Design seems low for a 8400lb trailer. Plus it's identical to the Crossroads.
Are you sure this is correct?

The only concern over "too long" is number of campsites you fit it. 30' fits in 35', but 35' does not fit in 30'! Depending on the type of camping you like, that could be a concern. Otherwise, there will be little towing difference between the two assuming the TV is capable of both.

Going down the road you won't notice the length towing one vs the other. With a good set of mirrors, you'll be able to maneuver both. The issue is going to be backing that 37' behemoth into any kind of a campsite...you will be looking for "big rigs welcome" and be camped in the pull-thru section along with all the folks in the a DPs that have their shades drawn.

That said, it's a great layout! Just think about where you intend to park it at home and where you intend to camp with it before you commit to a unit that big.

A properly equipped 3/4 or 1T tow vehicle and a quality integrated WD/sway control hitch will make it fairly easy to acheive. Payload and tongue weight may force you to a 1T SRW truck.

The second choice has 8400 lbs dry..
Do yourself a favor and get the 1 ton (350/3500) class pick-up. Very little difference in ride or cost but good extra cushion in payload.

I doubt you will notice much difference in towing considering the 4 ft. difference in length between the two.

With the proper hitch setup and tow vehicle, weight is a non-issue when it comes to towing stability. In addition, you shouldn't have sway unless some outside force creates it (wind, passing semi, uneven pavement). So the hitch setup is important along with the right capacity tow vehicle.

The extra 4 feet will be noticeable when maneuvering especially in tight situations.

If towing with the same truck you will notice a slight drop in MPG (maybe less than 1 MPG) and slower hill climbing speeds with the 2000 lb heavier trailer vs the lighter trailer.

My advice is to choose the trailer that fits your lifestyle and then buy a truck that has way more capacity to tow it. Plus get a good hitch setup. You'll have years of comfortable and safe towing. Don't skimp now if you have the opportunity..."go for the gusto"