If the mechanic says it's OK then yes - so long as it's a real mechanic and not an RV tech who usually knows a lot about RV stuff but wouldn't qualify as auto/truck mechanic. Agree with comments about tires which tend to rot from inside on RV's so outside looks don't give you the whole story. At a minimum I would have tire guy dismount the tires and inspect them - if they are real old tires I would even forgo that and buy new ones. If you buy new tires consider upgrading to E class but keep the tire pressure at D ... also - opinions vary on Tire mfg but many find that less expensive tires like Toyo work well on Class C's.
