We used to tow a 7500-lb (GVWR) 34' trailer with our 1/2 ton, and after 6 years of many long trips with that combo, I was tired of towing such a large one. (Weight was not as much as issue with us as was size.) We traded it for a 6000-lb (GVWR) 27' trailer and I (as the driver) am MUCH happier. It handles better, and we can fit into more national forest/state park/national park campsites with the shorter trailer than the longer one. I'd advise the smaller trailer you're looking at - even if you're considering upgrading the tow vehicle.
Previous comments on payload capacity of the vehicle and LT tires instead of P tires I also agree with. We did upgrade our tires to LTs a few years ago as well.
Before the current truck and the big trailer, we towed a 24' hybrid trailer with an SUV (Ford Explorer, before it was redesigned into a car) and it was not a pleasant experience. We did feel the "tail wagging the dog" even with sway control, due at least in part to the short wheelbase of the SUV. Another reason to choose the smaller trailer in your case. :)
