Calimark, can recommend the ACSI site at Eguisheim (The Three Chateaus). It's located within very easy walking distance of the medieval town (5 mins to get the baguettes in the morning!). The town is great, worth putting aside some time to explore and the vineyards are right behind the campsite with a self guided walk through them.Nice quiet site, good clean facilities and the ordinary rates can be cheaper than ACSI quoted. Some of the pitches are small and awkward for larger vans but no problem with the California. Been twice and would go back again.
There are supermarkets in Colmar, the town itself is also worth a visit, which is a ten minute drive away. You can also use the site to visit Freiburg in Germany, which is approx 25 miles away, across the Rhein (We don't like the site at Freiburg very busy with hundreds of seasonal pitches)
We will also be in the Black Forest last week in June.
Hubert
PS. If you want a site on the way to the Alsace region, can also recommend the ACSI site at Verdun (15-20 min walk outside the town). Again, good clean facilities.