It's a simple 1500 vs 2500 thread. I didn't even mention F vs G vs D. The 2500 the I DO have experience with, seemed a bit overloaded with a similar load as the OP posted. It wasn't fun to drive. If a 1500 is weaker, on any of the model years chosen, than the 2500 that I drove, I would avoid it. There's still plenty of used 2500's available everywhere.
The Suburban 1500 is very popular, I suspect that the over the top support for it here, is not because that it's BETTER than a 2500, but because 1500 owners are just trying to make themselves feel better about their own choices. Misery loves company.
If you're here, then obviously you're interested in more than an empty family truckster. Start off right, with the heavier truck that can grow a little more with you. Eventually the tear drop will make way for 16' TT. And eventually you might want to actually make good use of the 4wd and take advantage of boon dock camp sights. With the 1500, you might just find yourself in the same predicament as with the Toyota Sequoia you already have.
Start off in the many Yukon and Burb threads here, with many of them having the 2500 parts swapped in ala cart.