Unless Trail America recommends otherwise, I'd stick with cold pressure within the range on the side of the tire. Your trailer should indicate tire pressures for the loads it's rated to carry.
IF you were running Goodyear Marathons, they provide more specific information regarding the tire pressure of their SL-rated rubber... up to 10 lbs pressure above the max listed on the sidewall if you plan on towing above 65mph.
http://www.goodyear.com/rv/pdf/marathon_gen_info_032806.pdf