We've got a 30 ft Cardinal 5er that's 5 years old with 20,000 miles on it and original "Regul Trailblazer" LT215/85 R 16 tires. Tires have about 3/8 inch of tread left and when the light hits them just right there are some slight bulges in the sidewalls. We're planning a trip from Anchorage - Nebraska- Arizona - Anchorage for May/June. These tires don't look bad, but maybe it's time for some new rubber. What do you think?