Hahn is better than it was as they have expanded quite a lot. I've been using it fairly regularly since Ryanair first started using it as a base. They have some restuarants but everytime I'm there they are closed so I've no idea if they are any good. The don't seem to open in the evening.
As for things to do in the area - absolutely nothing.
tbh - spending 6 hours there would be a nightmare.
Hire cars are quite cheap - you are only 1.5hrs from Luxembourg, 1hr from Frankfurt, 1.5hrs from Koblenz if you fancied seeing abit of the area while you are waiting.