Here is a helpful list.
Click here. I think the most important thing you can do is have the dealer hook everything up, water, electric, propane, and holding tank drains. Make sure everything works. Make sure every question is answered. Ask how to winterize too, how to unwinterize, how to bypass the water heater. Have them demonstrate everything.
Note: RV refrigerators take several hours to cool down. They work very slow, but once cold work great. So if you have them turn the refrigerator on, don't expect sudden results. Instead, have them turn the refrigerator on the day before you take the inspection. Then it will be cold. You will know it's working.
Edit: I just re-read your post. Sorry... I put no value in hiring an inspector. I think inspectors are a joke. Like the above poster said, when they don't even know the diffeence between an electric line and a television cable, there's something seriously wrong. We tried selling a house. It ended up with 4 inspection. All 4 inspection (different clients), all came back with different results. One thing was ok with one inspector, it failed with another. Totally a bunch of BS!
Considering RV inspection is a relatively new market and demand, I wouldn't believe anything form anyone. It might be difficult for you, but YOU personally need to do your own inspection WITH someone you trust and believe in. That someone may be a friend, and it might be someone you hire.... BUT .... YOU need to be there when they do it! You still need to ask questions, and if your friend, or your inspector says there's a problem,.... you can ask him/her immediately.... "WHY?" Then talk to the dealer about it. THERE IS NO SUBSTITUTE FOR INSPECTING YOURSELF. NONE!