You could consider a day trip on the Danube river or a bus trip. There is Melk, Durnstein and Krems to visit. Richard http://en.wikipedia.org/wiki/durnstein http://en.wikipedia.org/wiki/melk http://en.wikipedia.org/wiki/Krems_an_der_Donau

Am not a hiker but I like to walk. You might take bus 38a to Kahlenberg for an incredible view, then take the footpath down to Grinzing for a meal or wine at a heurigen. From Grinzing the tram goes back into Vienna.
There's a great trip report on Vienna by mademoisellefifi, which I can't find. It has fantastic detail and photos on Vienna's architecture.

The Vienna Woods is a great place to hike, and there are some tram stops that will get near some entrances to it (can't remember which ones, though, as it's been a while).

If you are a big classical music composer junkie, there are several houses one can visit besides the Mozart one (at least 3 Beethoven houses, Schubert's birth and death houses, a Haydn house that has a memorial room to Brahms as well, and a Johann Strauss house), plus all these folks are buried pretty much next to each other at the big cemetery at the southern edge of the city.

Another vote for Melk and Durnstein.

Forgot to comment on your itinerary. It seems fine to me -- very realistically paced and should allow you to experience everything in depth. You could indeed add something onto your Belvedere day if you wanted.

Melk Abbey makes for a good visit

www.stiftmelk.at

But March is not the best time to visit this Melk- Wachau- Dürnstein- Krems area.

Melk Abbey still on its winter schedule with limited visitation- guided tours- most times just twice daily in english.
The boat cruise on the Danube Melk- Krems is great but this does not begin until Mid- April

www.ddsg-blue-danube.at

Dürnstein is still asleep in March. Most shops and restaurants closed.

Tourist season does not really begin there until mid April when tour boats begin the season and the Danube cruise boats begin to arrive.

Good advice from molker. I think, if you intend to return to this area, these sights could wait, perhaps for a busier season. But if not, you could still consider visiting on a bus tour. No boat ride during the winter schedule, but then lunch is substituted. Tour runs Wednesday and Saturday for eight hours. www.viator.com/Vienna-attractions/Wachau-Valley-tours-tickets/d454-a537

Thanks for all the feedback folks.
I was having a hard time trying to figure out what to drop to make room for a daytrip, so it is probably just as well that it won't work out very well. I will just have to go back someday.

Cathinjoetown - I found Mademoisellefife's TR, thanks it was inspiring.

bachslunch - there seem to be 2 separate cemeteries - St. Marx's which has Josef Strauss and Mozart; and Zentralfriedhof- which is much larger and has a special section containing the final resting place for Beethoven, Schubert and Brahms, among others.
St. Marx's is a little simpler for me to get to (looks like to 30-35 minute walk from my hotel), but I will see how it goes.

I think Stage 1 planning for Vienna is settled (and bought my ticket to see a performance at the Spanish Riding School this morning!). Next two stops (Munich and Berlin) are already done, so now it is on to Paris!

glenmd; Look for yk's trip extensive trip report on Vienna, written in May of 09.

If you're interested in the Vienna Boy's Choir, they perform at the 9:15am Mass at the Hofburg Chapel on Sunday mornings. Looks like they will be there the last 2 Sundays in March and the first 2 Sundays in April if any of those dates fit your schedule.

I attended the Mass (stayed in the vestibule where there is a split TV screen so you see Mass on one side and the boy's choir on the other side). After Mass, I had tickets that morning (around 11am, I think???) to the Spanish Riding School performance. So, timing-wise, it worked perfectly!