Emergency parts on the road

Unless you know you are not going to be near a place where parts can be purchased as needed, I see no need to try to carry a mobile workshop to cover every contingency. I do carry a tool kit. Parts can be purchased as needed. Sometimes parts go bad that you would never anticipate. I had a propane pigtail hose go bad. The internal valve stuck and was keeping adequate propane from flowing. I had to stop and purchase a new one. I would never have thought that the hose would go bad, but after I replaced the regulator and it still didn't work, I figured out it was the hose instead. A spare filter and spare fuses are lightweight so they can be carried without adding a lot of weight or taking up much space.