jwiz7, at 10 yrs. old a diesel coach will start needing new tires, possible air bags, new shocks and other items as they start to age.
But, even comparing a new gasser to a 10 yr. old diesel coach is still not a apples to apples comparison. The diesel unit will still have a more robust chassis and robust parts attached to it.
As you are seeing, that's the point where a lot of gas coach owners feel comfortable jumping into a diesel as the prices are more affordable. In my opinion, if I was in your shoes, I would choose the top-of-the-line coach of the brand that you like. They will usually have top quality cabinets and other upgrades like Aqua-Hot, washer and dryer, tile floors, leather furniture, etc.
MM.