Mine is a 99, but here are some thoughts I have:
Check Tire dates
If you can run the water system, check this. I had a broken gray tank drain pipe I didn't find until the spring thaw. Also the fresh drain was capped. (I think the PO didn't know about the drain valve)
leveling system. If its a hydraulic system, run the jacks all the way out to the ends while your leveling it. look for leaks, then retract, make sure they retract all the way.
Slide extends and retracts without binding, look at the seals to verify they look good, but also seal all the way around when in and out.
If you have a voltmeter, check the house and chassis batteries in theses three conditions: No shore power, shore power, and then engine running. This will give you an idea of the battery condition and also if the BCC is doing its job (switching in to allow the engine to charge the house, and when on shore power, switching in to allow the converter to charge the chassis battery.
Check to see if battery disconnects work.
Check the info center to make sure all the switches and tank level sensors are indicating correctly.
I don't know anything about the Workhourse chassis. But maybe take a look at tranny fluid to see if its been serviced and /or has any burn smell (also nice brite red color)
I take a piece of cardboard to crawl under, look at U-Joints, exhaust system, Shocks, and you might be able to see how much material is on the brake pads.
I put together a
pre-purchase inspection checklist I use. Your welcome to use it to get more ideas on things to look at.
We just bought ours a few months ago and are absolutely in love with it.