I'm pulling the Montana HC with 12,500GVW, right at that weight. Heavy loaded for a 2-4 week trip I run about 4500# per axle and 3,000+# pin weight. I have 5200# axles and 6 lug hubs. I went straight to Discount Tire after buying the trailer and put 230 80 16 E Maxxis on it. Ran them almost 4 years with no issues. Last spring I replaced with the new Carlisle HD, same size. One long trip and a couple short trips, no issues. You can get the Carlisle HD for about $50 through WalMart.com, delivered to your store, mounted free. I got Discount to match that price.
Get to a CAT scale when you get home and get your axles on different scale pads. You should be fine. Get a TPMS. Air to 80psi. Check often. I check temps with a infrared temp gun on the tires and drums at most fuel stops.