I just went down this road a few months ago. Once I saw what shipping tires costs, then paying a place to mount/balance/disposal and not have any local recourse for problems turned me off of online tires. Throw in you may/may not have a choice of date code which for RV's is a pretty big factor of value. I think part of the schtick to online tires is some of their inventory is getting stale. So irrespective of brand, be sure whatever deal you're getting has value above the time and effort you'll put into it.
Mark B.
Albuquerque, NM