Well, I guess I shoudn't offer an opinion here, because the MOST important tire issue to me is SAFETY. :-laf

sorry couldn't help myself.
I have only run the Michelin LTX/AT2 265/75/17 E and now the Toyo Open country AT 285/75/17 E. BOTH have been an excellent handling tire in all weather conditions, though I have not yet run the Toyo in snow. That being said, people are not getting much more then 25k to 45k miles on either of these tires, but everyone here pretty much agrees that they are both safe and quiet in operation.
They Toyo in the 285/75/17 E has a #3950/tire load rating, while the Michelin in stock size is rated at #3150/tire. I loved my Michelins, but woire them out at 25k, I HOPE to get more from the Toyos, but only time will tell. They DO come with a 50k treadwear warranty in all 17" and under sizes. The Toyos certainly LOOK better (fill the wheel well, but do not rub at all), and even MORE importantly to me, the larger diameter helps to drop my RPMs at highway speed down to an acceptable 2000, as opposed to 2250 with the oem tire size. They are on of the few tires E rated that are being made in the 285/75/17. That being said, with your towing loads as stated, you probably do NOT want the drop in rpms.
Nitto also makes the DuraGrappler in the larger size, which is E rated. It is a highway tread, and some people here also LOVE it. Please note, though, thst the mileage warranty on the Nittos do NOT apply to the larger sized tires. THE Nitto treadwear warranty applies ONLY to the tires labeled DuraWear on the sidewall.
For what it is worth, these are the ONLY tires that I would consider for my driving needs and conditions, which are admittedly and importantly DIFFERENT from your driving needs and conditions.
Good Luck--let us know what you decide. There are MANY excellent tire threads already posted here on TDR... do a search and read to hearts content!! Oo.