Hi Laura, which ever time of the year you visit Alsace, you’re in for a treat. The villages are a bit hectic though during harvest time from September to November. Alsace is unique in many ways and possibly the only place in Europe that I know of, where you can have French cuisine with proper German portions.
I could make it a very long post by listing my endless recommendations. Instead, I will just mention what you must not miss and the rest will be left to your intuition and local input while you’re there. Although there are so many beautiful villages and towns, do not miss a drive along the Route Du Vin d’ Alsace and include at least a stop at the following: Strasbourg, Haut Koenigsbourg, Bergheim, Ribeauville, Riquewihr, Colmar (and Petite Venice), Eguisheim, Rouffach.
If you’re after a culinary experience to remember for a long time, try the 3-star L’Auberge de l’Ill (Illhaeusern). For a no frills meal but excellent food and value try the Le Comptoir A Manger in Strasbourg and the La Grenouille in Riquewihr. As is always the case in France, make sure to book well in advance.
As far as wineries go, a visit to the maverick Pierre Frick in Pfaffenheim is a must. The guy has elevated organic winemaking to a new level. Domaine Joseph Gruss and Leon Beyer (amazing old Brewery cellar where they store their wines) in Eguisheim, Domaine Schlumberger in Guebwiller, Doppf Au Moulin in Riquewihr (some of the best Cremants), Kuentz Bas in Husseren les Chateau (excellent Alsace Pinot Noir on top of the usual wines).