Lindau, Germany

It´s out of your line of travel... but yes, it is worth your time. I probably wouldn´t spend more than a day there.

it is loverly and should be grouped with a vist to King Ludwigs other castle nearby, Neuswenstein.

If you're going by train, spend a couple days in Salzburg and then you can continue to Venice (via Villach). Another choice could be Verona (via Innsbruck). Lindau is a good half day stop if you're going to Switzerland.

I like Lindau (been there five times - day trips). Nearby Friedrichshafen (Zeppelin Museum) is also woth a visit. However, they're more than just a little out of the way. Traveling from Munich to Venice, I would spend time in the Oberbayern area between the Munich/Garmisch-Partenkirchen rail line and the Inn river. There is a rail line from Munich to Holzkirchen, then the line makes three branches to Bayerischzell, Bad Tölz, and Tegernsee. If you go to Bad Tölz you can then take buses to Kochelsee, and Walchensee, and eventually to Mittenwald, then over the pass via Seefeld to Innsbruck.

I like Lindau, too. I used Lindau as a base (first night, last night) for biking around the Bodensee (Lake Constance). Beautiful area. Another option would be to stop in Bolzano and see Oetzi the Iceman at the museum; the town itself is also worth at least a half day or whole day. Rental bikes there are really cheap. :)
In what month are you traveling?

We will be traveling in April. Thanks for all of the info it helps

The Lake Constance area is a detour for you, but a wonderful area if you can work it in. Better than Lindau is Meersburg for at least an overnight. If on a Eurail pass, take the trains from Munich to Friedrichshofen for easy bus connection to Meersburg. Then by short ferry ride to Konstanz where a bus awaits for transport to the train stations (side-by-side German and Swiss rail stations). Swiss rail will take you to Milan. But you are talking about a LONG trip to do all this!!! Check rail schedules at www.bahn.de. Another option is to head south from Munich and spend a day or two in Berchtesgaden, from where Salzburg is an easy day excursion by train or bus. Then from Salzburg, head down toward Venice.
I think I would save Lake Constance for another trip....

We used 3 days in Lindau at the end of one active vacation as a place to relax and wind down before flying home. Not a lot to do, just a lovely little place- of which there are many in Germany.