I've got a cleanco compact and there isn't too much to worry about compared to my old air-cooled slide-in.
The hose that runs from your fresh water tank to your pump has an inline filter that should be checked and cleaned periodically. If it gets clogged restricting the flow of freshwater, I noticed the pump will draw a lot more from the chem metering jug which is bad for the carpets.
My blower is dual oil splash so it has no grease fittings. Yours might be the same.
If you don't know if the blower and cat pump oil have ever been changed, do it or get it done on that 3 hr trip to the disty.
Keep a log of all these oil changes and van oil changes. Write down machine hours and van miles when you do.
If you ever suck waste water thru the blower, make sure you haven't built up deposits of crud on the blower. When the machine is off I reach down next to the drivers seat and give the pullley a spin to see if it turns freely. If you start to notice it is getting tight or sticky, run water thru the blower to flush it out. (If you wait too long it can seize up)
Make sure to let it run dry before shutting off.
Keep your blower filters in the waste tank clean! You'll notice if you forget. (Wetter carpets)
The vac guage on my panel is connected with a small quick connect like most of the other panel items.
This is kind of bad because it can give a lower than true vac reading if connector leaks. I overtightened my vac release in the
beginning before I noticed this.
There are no u-joints on the drive shaft for my cleanco and I haven't noticed any servicable grease fittings on it, but now I will check again.
There really isn't alot of maintenance to do on a cleanco.
Keep an eye on the hose clamps on the radiator lines that run to the heat exchanger. Had one go and dump most of the coolant out. Luckily I was driving and not working 3 floors up where I wouldn't notice until it was too late. I added a second one to each place that had one.
Some guys install a coolant temperature monitor on the truck engine that shuts engine down in case of overheating. I couldn't figure that one out and will someday regret it.
Installing a small dam to keep water overflows or leaks from running under the front flooring and seats is something I always do. That insulation takes forever to dry and will cause the floor to rot out.
Its been discussed before online. Angle iron or aluminum, screws, caulk, and planning.