I don't like this year's arrangement. To me the attraction L'Etape is get to do a full stage of the TDF with conditions as close as they can be to the actual stage. And it needs to be one of the epic mountain stages.
So the L'Alpe de Huez option misses the criteria because its not a full stage
And the St Flour stage doesn't meet the Epic criteria.
Unless you go to L'etape on a recurring basis, I'd skip this one.
And if the attraction is doing the Telgraph, Galibier, and L'Alpe, La Marmotte may be a better option
http://www.cyclomundo.com/marmotte.html