As I have previously posted, the Ford V-10 is about as reliable as you can get. One friend had 350K on his truck and another 495K on his. One was totaled thus ending it's career, the other one got a new engine.
Cylinder spark coils were common occurrences and water pump was the next. A serpentine belt is good to have and get those hoses checked and replaced. Yes, it can be costly however on the road you will pay 3x as much.
Regularly scheduled maintenance using quality parts and lubricants is the best extended warranty you could ever invest in.
After EVERY trip, I get my creeper out and take a slide under my rig with a flashlight. Loose wires and broken zip ties are common.
Become friends with a mobile RV mechanic. They usually charge much less that a brick and mortar repair shop and they come to you.
My dad's cars could make it to 100K and after that they struggled, those engines are long gone. Today's engines are so much better.