Germany, with 42,000 km of rail, has the most extensive train system in Europe and the second most dense, second to Switzerland by only 1%. Bavaria, has over 1000 stations, so you can go almost anywhere, plus, the rail system is augmented by a robust bus system, including the German Rail subsidiary, Regionalverkehr Oberbayern (RVO) with an extensive network in SE Bavaria.
It helps to know the fare system. Between advance purchase Savings Fare tickets for longer trips on express trains and day passes such as the Bayern-Ticket in Bavaria for shorter trips on regional trains, public transportation can be economical.
I find I can get to anywhere I want to go by using public transportation, including small towns, which make up 85% of my venues.
Sometimes I go to Germany alone, sometimes with someone, but I am always the one who would have to drive. I like sitting in a train or bus, looking at the scenery, reading, writing my journal, whatever, to watching the road. And I usually save hundreds of dollars in the process.