Hey Scotty,
I bought a used 2004 E350 Extended cargo van (private party) and have spent the last 2 years of my life converting the interior into a pretty awesome camper build. The van has about 100k miles, and seems to be in great condition. Since I put so much time and effort into the build, I want the thing to last as long as possible. I'm thinking of taking it in to my local Ford dealer and having them do some work you've recommended in your videos on how to make cars run longer (change trans fluid, air filter, spark plugs, and new synthetic power steering fluid). Anything else I should have them do or check?
Thanks, big fan!
Taking your vehicle to a Ford (or any other) dealer will be the biggest mistake of your life. Find an independent mechanic for the work you want done.
If you intend to keep it for a while, then invest in the Haynes manual (or AllData, if you like electronic version). Review the maintenance section and be familiar.
The air filter you can certainly do yourself for way less than a dealer. And the spark plugs should be relatively easy too (lots of Scotty videos showing how to replace plugs). I don't know that model, but steering fluid is usually easy, too. The transmission fluid is probably more advanced service and justifies taking it in.
The more you can do things yourself, the more you will be incentivized to maintain it well. And especially since it is obviously intended for travel, it will be good to know how to service and fix things on the road.
Welcome new member!
Good advice here from @Dad2LM2