A two night stay runs the risk that you won't get good weather for the Jungfraujoch. Of course, it's a pretty cool feat of engineering, if you're into that.
Driving to Liechtenstein will take at least three hours. There could be snow on the Brünig, and then it will take a lot longer than three hours, or you'll have to drive via Bern, and it'll still be pretty long. However, if you're driving to Munich from the Berner Oberland, you'll be going right by it. And then it's not a major detour.
If you do end up going to Liechtenstein, head up to Triesenberg for some nice views of the Rheintal.