If you have a family of 5+, go for the Suburban/Yukon XL. 3rd row seat is usable plus storage behind the 3rd row. I recommend captain chairs in second row for easier access to the third row by children. The 5.3L/6-spd/3.42 is good for towing. While the 6.2L offers more power, it is not necessary for mountain towing and recommends mid+ octane for towing conditions. Make sure the vehicle you select has the 3.42 and HD Trailering equipment. This can be confirmed by the option codes GU6 and Z82 on the RPO sticker in the glove box. Many full sized GM SUVs are made without these which affect tow ratings as well as real world towing experience for RVs.