After 15,000 miles of towing a TT I bought used, I just changed the tires because they were dated 2009.
They were the factory tires, you know those dreaded China bombs that everybody frets over.
The RV industry has put 1,000,000 tires on the road each year for the last three years, so naturally they select the least expensive tire that will do the job.
If you want to feel safe then by all means buy the best you can, road hazards like to puncture them also.
Oh and surely you are not going to tow with anything less than a diesel with dual rear wheels, you know those crosswinds and all.