I used a beeswax product on the stuff that was in good shape. The stuff that needs help (was scratched up or worn down to bare wood in places) I have just pulled out of the trailer and sanded down, and I'm staining it with a stain custom mixed by a local shop. I took a good original panel in and they gave me back a three step procedure and custom mixed stain with a satin finish topcoat they felt would get as close to the original as possible.
I also sanded down the cabinet frame because it appears it was never stained, it was painted originally. It's going to look a lot nicer stained and will match the stained panels better. Here's the work in progress.