Thanks. Checked on this, and apparently the only "heavy modification" needed was to reinforce the hitch itself, which had a tendency to crack even under factory load on the <2012 models. Thankfully not an issue anymore with the new models, unless I'm towing something ridiculous.
Right now, leaning towards the Surveyor SP260 or 280. These are streamlined and have a low height, under 9ft, which will greatly reduce wind resistance. And, at 4141 dry, with a 469 dry hitch, even adding weight, I should be doing great, by the numbers? Assuming this will climb to about 5200 loaded, and probably another 100-150 on the hitch.
