wine and drive are words not normally used together in Europe!!
Stuttgart is a large industrial city (Mercedes-Benz and Porsche to name two). It has a few museums in the centre but if you aren't interested in cars you can do better.
Baden-Baden - why, apart from the drive? The B500 which runs all the way from the border to Baden Baden is a great drive but takes over 4 hours without stops.
Freiburg in Breisgau (best to use the full name, there are a lot of Freiburgs!). Really nice central district and quite a nice drive to get there. From Zurich head to Koblenz (the Swiss one, don't let Google plot a route to the german city!!), probably on road 17 from the west side of Zurich. Cross the Rhein at the Koblenz/ Waldshut border crossing and follow the road through Waldshut to the B500 then take then and head north. Excellent scenery and a well made road. Passes alongside a couple of lakes, Schluchsee and Titisee, good places for a coffee stop. When you reach the intersection with the B31 turn left to Freiburg. Then if you the facilities in the town of Titisee take the next exit, this road has a large parking area by the railway station and rejoins the main road at the other end. Carry on following the B31 towards Freiburg. I don't recommend trying to take the car into the centre (they don't want you to!) so park and use public transport which is cheap. Pull off the B31 at Kirchzarten, park at the railway station and take the train, these are every 30 minutes and take 14 minutes to the main station, then walk or tram to centre. Or, leave the train at Freiburg-Littenweiler and walk a short distance to the tram terminus north of the station and go right into the centre by tram (Bertolds Brunnen is the real centre stop) . If you come out of the city by tram you need line 1 to Littenweiler (Laßbergstraße). The train/tram ticket is a day pass good for travel on all regional trains, city trams and buses. See https://www.rvf.de/fileadmin/user_upload/techdocs/prospekte_rvf/rvf_17_regio24_flyer_web.pdf and note that there is ONE ticket that will cover up to 5 adults (ie a car full) - do not buy one ticket each!!!! You could half the price of the transport pass if you could find your way to Littenweiler station and find somewhere to park there - best of luck with that!
Just wandering around the old town and having lunch will fill up 4 hours without going into a museum.
http://www.freiburg.de/pb/,Len/225797.html
An alternative route back from Kirchzarten to Zurich is to take the road south out of the village to Todtnau, then turn left and follow the B317 over the Feldberg (ski region, season will be ended but you may get a glimpse of snow on the peaks) until you ge back to the B500 then head south the way you came.
Allow 3 hours travel time each way (including coffee stops and train/tram)