Towing in 3rd gear rpm high?

when I bought the camper I showed up at the dealer and I went to check the tire pressure in the camper tires before I left and the tires were so dry rotted they had leaked 15lbs of air since the day before and one of the valve stems broke off while I was checking the air so the dealer panicked about loosing the sale so they gave me the new wheels and tires off another unit that they upgraded to aluminium wheels. I lecture wheels because they really didn't bother me but I'll probably paint them white to match because I plan on buying a new camper next year and I think resale value will be better with them being white.