fonna be there for 3-4 days

planning Parktnakt gorge and Zugspitze

anything else we can do?  we will have a car

around beginning of October.

we will already have done Oktoberfest, so skip that...

and or good places to eat/get drank on

will be staying by ski jump

good talk

Also would be nice in either Munich or Garmisch to find something "romantic" to do with the wife--a suprise.

any thoughts on that?

I would love to help you, but i have never been to Oktoberfest/Garmisch/Zugspitze and the last time i visited munich i was like 12 Years old

Maybe you can find something here:
http://www.gapa.de/Garmisch-Partenkirchen_Excursion_destinations

We are a chatty bunch here!

Other then walk, there is not really much to do in G-P that you can't do in any other Bavarian town in the summer.

Normally go to Berchtesgaden area in the summer as there is much more to do. G-P is more a winter ski destination.

Mittenwald looks nice---may go there for a visit

If you are a big fan of beer, visit furstenfeldbruck.  The Konig Ludwig brewery there has some of the best beer in all of Germany based one the hundred or so different German beers that I have tried.  
The views on the way up Zugspitze are phenomenal, and the long route can be done with some water and a good pair of boots.
The gorge is amazing by the way.
Lake Starnberg is a nice relaxing trip, and you can finish the day with a visit to the Andechs Monastary for some tasty food and beer, especially their doppelbock!
Schloss Neuschwanstein is quite a nice place to visit.

Hope this helps.

Also, I spent two months in Munich this summer, so I will try to answer any questions.

headed out today

think we are going to try the hike from garmisch to mittenwald... looks like about 10 miles--should be doable-- take train back

and will hit up the cable car to top of zug.  

for the next four days ita all about Munich and Oktoberfest though..

late but moar info:
-Oktoberfest was frigging awesome-- don't remember much...lucky I got pics.  weather was perfect.  soo much fun dranking with locals/other travelers.  everyone was super nice.
-wandered Munich--never felt threatened at all, just a bunch of people touring about and drinking
-did a bike and Neuschwanstein castle tour--weather was PERFECT
-stayed in Garmishc--had good weather first day we got there-- went straigt to Zug--took cable car up--way better than train
-Sport hotel in Garmisch was awesome---we got kicked out of spa/hot tub....because we had swimsuits ON....lol...
-hiked partnakt gorge--again.  still awesome.  found gasthaus on route...got drank on.
-hiked a gorge in mittenwald--was also awesome.

was a great trip.  now kids are bugging me to go to Europe--found some 550 flights to Italy in October....hmmmmm