My husband and I are going to be in Munich for three nights in early September (staying near Marienplatz). Based on reading, we would like to visit Neuschwanstein, Hohenschwangau and Linderhof. Is it possible/advisable to rent a car for the day to visit all three? I see that most of the bus tours only see one or two of these, and we like the idea of "doing it on our own." At the same time, we don't want to take on more than we can handle! Any advice on what car company, itinerary, what day to go (could do sunday or monday), travel route, and sights to see on the way would be greatly appreciated.
3 nights is actually only 2 full days. With that short of a time in such a wonderful city I can't fathom why you would want to leave and spend your time driving or riding a train or bus. Neuschwanstein area is certainly nice but deserves more than a quick arrive and depart - an overnight is wonderful there and would allow you time to see nearby Linderhof.
I just spent 3 nights in Munich then rented a car a drove around Bavaria and the Rhine region for 14 days. If you rent a car super early in the morning you can do it. Go to Neuschwanstein first (before 9am around 8am there are no lines) then hit Linderhof on the way back. We enjoyed Linderhof much more than Neuschwanstein. So I think it is a must do. Our best day in Munich was renting bikes from Mike's Bikes (show your RS book for discount, you must show the book. They had no idea until I showed them where it stated the discount). Ride around the English Garden, stoping to swim in the river, watching the surfers, and enjoying the beer gardens. You can even ride to Olympic Park and enjoy the sights over there also. If you decide to just stay in Munich I recommend walking around the summer palace over the Residence. We enjoyed the grounds and the small hunting lodge much more than the huge boring winter palace.
Make sure to make reservations for the castles. You don't want to waste time sitting around for a tour. We did not need reservations for Linderhoff when we visited but we did for the other two.