Greetings Teresa and Rick!
There are many preferences regarding tires. When I chose tires for my coach, my travel pattern was very important in my decision. Since I travel great distances with my Airstream nearly every summer, having readily available dealer support for the tire chosen was critical. It was a rather easy choice since I usually run Good Year tires on all of my vehicles, the Good Year Marathon became a natural choice for both of my trailers. I haven't used anything other than Good Year ST trailer tires on any of my trailers since 1980; and have been quite pleased with all of them with the sole exception of those that came as factory equipment on my '80 Nomad - - Skyline had built the coach such that the tires were maxed out at the empty weight of the trailer so they had a VERY short and explosive life.
I am currently running P225/75 R 15 ST Load Range D tires on my '64 Overlander (6,000 pounds Maximum Gross Weight); and P225/75 R 15 ST Load Range C tires on my '78 Argosy Minuet (3,250 pounds Maximum Gross Weight).
I am convinced that one of the best indicators of where to purchase tires is the level of satisfaction that you have with tires that you use on your daily driver - - if you are confident in your dealer then consider the tires that he has to offer - - especially if much of your traveling will be within his service area.
Good luck with your decision!
Kevin D. Allen
WBCCI (Lifetime Member)/VAC/Free Wheelers #6359
1964 Overlander International/1999 GMC K2500 Suburban (7400 VORTEC/4.11 Differentials)
1978 Argosy Minuet 6.0 Metre/1975 Cadillac Eldorado Convertible (8.2 Liter V8/2.70 Final Drive)