Regardless to where you will eventually fly in and out, the region you will be staying in is so rich in culture and sights that you do not want to waste your time going elsewhere with the limited time you will have.

Freiburg has a beautiful old town, nearby Koenigsbourg castle in Alsace is your quintessential castle, the Black Forest with its charming villages should have some decent snow then. Nearby Basel is a major hotspot for arts and museums. And so on. Most destinations can be easily reached by public transport, taking the local rail routes thru the Black Forest will give you many nice vistas.

Btw.. Basel airport is the nearest serving Freiburg, with a regular bus shuttle. If it makes no big difference farewise it would be the ideal gateway to get in and out of Freiburg.

Check out some trip reports at Bavaria Ben's website - www.bensbauernhof.com. Especially Ben's reports. The past few years he has been more 'Black Forest' rather than 'Bavaria'

Hr

But Basel doesn;t have transatlantic flights. To get there you have to change a the dreaded LHR or CDG - or even worse Frankfurt. IMHO better to just fly into Frankfurt and hop on a train than waste all that time changing flights.

And, IMHO, Basel is a really boring town. Had a client there and visited often - and everything shut down at about 9 pm.

"I plan to make my itinerary around either Zurich or Munich or both due to flights."

Zürich is MUCH closer to Freiburg than Munich. And there's a lot to see around Freiburg.

I could see a few days in Freiburg with day- or overnight trips to Colmar, Strasbourg, and places in between - like Cowboy's suggested Koenigsbourg (castle info: http://www.haut-koenigsbourg.fr/downloadfiles/download/2C5C0FA1-2C15-438A-B749-712640329DDB_442.pdf ) Then you'd have a couple days for the Black Forest area and maybe a day in Zürich before heading out. In the Black Forest, a daytrip on the Black Forest railway to Gengenbach, Haslach, Triberg, and Schiltach (offshoot line from Hausach) takes you through the highest part of the BF. Gengenbach is an attractive old walled town of cobblestones and half-timbered buildings not unlike Rothenburg and a good place to overnight.

http://www.stadt-gengenbach.de/en/tourism/old-town/
http://www.black-forest-travel.com/gengenbach/
http://www.black-forest-travel.com/places-of-interest/black-forest-railway.html

Double-decker sightseeing trains on the BF Railway:
http://www.bensbauernhof.com/russschwarzwaldbahn.jpg

If you stay in Gengenbach or other small villages in the BF, your train outings are free because of the Konus program:

http://www.blackforest-tourism.com/konus

Outings from Freiburg into the BF will run 17€/day for a Baden-Württemberg ticket single (daypass):

http://www.bahn.com/i/view/GBR/en/prices/germany/laender-ticket.shtml

Villingen is another nice high-elevation town on the eastern edge of the BF and on the BF railway line mentioned above:

http://www.tourismus-vs.de/en/views-of-the-city/sights/villingen.html

If you end your time in Germany in Villingen, a trip into Zürich is less than 2 hours by train and costs as little as 19€ with an advance-sale ticket from DB (German Railways.)

http://reiseauskunft.bahn.de/bin/query.exe/en

I did not suggest Basel as a replacement for going to Las Vegas or New York City's nightlife but because of the museums. And even there I doubt that many museums stay open in general after 9pm.

There is no big difference in changing planes or plane to train in Frankfurt. So I don't get what the massive upside would be to do the latter. Unless you like even longer walks and a non-secured connection plane/train vs a secure connection plane/plane at CDG or LHR.

I agree with staying in the area because of limited time, but I think the OP wants to be based in or very close to his/her city of departure so they don't have to worry about rushing to the airport from afar or taking the second last day to move to an airport area hotel.

Zurich, being closest is probably the best bet to keep your options open. It has a rail station right at the airport (as does Frankfurt) and you can get there in about 2:15 (2 options arrive before 10:00 a.m.) with one change in either Zurich's Hauptbahnhof or Basel.

Obviously, Zurich is an even easier choice and Basel at 1:15 direct to ZRH is good too, but if it were me, I would probably either stay in Freiburg and find some day trips, or head over to Strasbourg for a couple of nights and then either leave really early for ZRH (06:51h -> 09:46h) train, or head to ZRH late the day before my departure and stay at an airport hotel, or leave early and stay central so I could tour Zurich on the second last day.

As for "boring" Basel, I agree with Cowboy There isn't much (legal) action in Butte, Montana after 9 p.m. and it is really dull at Head Smashed in Buffalo Jump after about 4 p.m., but that didn't stop Cowboy's from visiting both of them. It ain't always about the nightlife.