Hello
Sounds like you are getting some good advice. Personal experience, bought first used diesel pusher 2 years ago, a 2007 with original tires and less than 50,000 miles on them, no cracking or checking visible, good even tread. First long trip on I-465 in Indy, blew driver front tire , lucky it was on the inner sidewall and not a shredder. Trust Me you don't want to take a chance on this, I will replace my new tires at 5 years.
sparkchaser