Hello,
Sounds like you take really good care of you chassis. It really hard to tell how much longer until you have any problems. By doing all of the periodic service on the coach you have done just about everything you can do. I have see coaches that have had twice you mileage and have never had any problem. On the other hand I have see coaches that have 10,000 miles that have lost a motor. As long as you don't drive it wild and keep taking car of the chassis you may not have any other problems for a while. When part decide to go bad a lot of times there is no warning or very little warning. Listening for weard or abnormal sounds is a good way to keep and eye on the condition of the chassis. You would know better than any one else when a problem is starting to happen due to you have driven it more than any one else.
Just keep and eye on the fluids, keep changing them at the regular service periods, and when you hear something that it has never done befor, Well that would be you first clue a problem is starting to happen.
You should be able to enjoy you coach for a while longer.
Hope I was able to help.
RV Mechanic
10 years of experience, 5 years Master Certified. Factory trained to repair RV equipment.