He'll want to find the source of the water that is creating the musty smell. Do a search for leaks and you'll find lots of things to look for -- sunroof drains, windshield (front and rear) seals, etc. Once you've found that, pull and thoroughly clean the floormats and the floors.

I somehow talked my wife into letting me buy a 300D to supplement my Miata as a daily driver. I love the Miata, but 2+ hours/day in traffic is not its forte. My criteria? Cheap (<$5000), 25MPG or thereabouts, comfortable, reasonably quiet, plenty of headroom, and has some style or identity. Cars that fit -- old Mercedes (primarily diesels), and...?

Now as long as my wife (who's been surprisingly understanding so far) doesn't pay too much attention to the credit card bill that's coming this month, I should be OK. It turned out that the one I bought needs just about everything that a 300D needs by 120k miles.

__________________
Tim Irwin
1983 300D
1994 Miata R Package
unnamed family car