Assuming you are talking about a Powerboost hybrid? A limitation of the Powerboost seems to be payload capacity of 1830 lbs before options. Once you add all the heavy options on a loaded truck that number goes way down. Limited powerboost has payload of as low as 1100 lbs (verified by...
I believe hitch weight of trailer counts against payload so might still matter. Does a horse trailer not have much hitch weight?
I'm running these scenarios as well. 4 people in truck = 600 pounds, no gear in bed, WDH = 100lbs that leaves only 600-800 left of payload capacity for the...