I would narrow it down by what regions they are going to visit. If she likes white wine Alsace, the Loire or Burgandy. Red wine Bordeaux or Burgandy. Check out the vineyards they actually visit can you find an independent rating of their wine such as in Hugh Johnson. Personally we just e-mail and make appointments with the individual vineyards we want to visit. Everyone has been hugely helpful and had lots of interesting information. I have appointments in the Loire and Bordeaux in a months time. Another option if she likes Champagne is to stay in Epernay you can then visit Moet, Mercier and De Castellane without appointment all are really interesting in their own individual ways.