I spent several years in the area, and visited Baden Wuttenberg on many occasions. Freiberg is a lovely university town, with a heavily pedestrianised centre, bustling on a Saturday, which is when I'd recommend you visit.
Baden-Baden is a more exclusive town, with an older demographic. It was England's base during Euro 2006, so very WAG friendly
From what I recall, you'd see all the sites in a day (the casino is well worth a visit).
Heidelberg and its castle, further north, is beautiful as is Ludwigsburg Residential Palace near Stuttgart
If you're in the area, I'd highly recommend crossing the border in Alscace. Colmar is very close to Freiberg and is a very pretty medieval city. If you have the time, the "route des vins" is a lovely trip to do especially on a warm summers' day, there are plenty of people who cycle it, if that's your cuppa, with numerous stunning villages dotted around the hills to see too (Riquewihr, Kayersberg, Ribeauville etc).
You're also likely to find things which are open on a Sunday there (including the vineyards), whereas most everything else is shut (shops, supermarkets etc don't open, unless they're in a train station). Haut-Koenigsbourg Castle is very impressive and there's a large car museum near Mulhouse (skip the town itself though). Strasbourg is a nice walkable large city too with plenty of attractions.
Europapark is a fantastic theme park, near "Rust" in Germany. but there are also loads of "
luge" on both sides of the border which kids (and big kids) will enjoy.
It's a fantastic area, which I'd highly recommend anyone seeing. Enjoy your holiday.