Why make life complicated?
Last time I did it in an old C.172 in June was to exit zone going north at point 'N'.
GPS track direct to Troyes passing on top of Grenoble(Le versoud).
Fantastic flight , constant climb to about 10,000 ft and gentle descent. Still snow on the peaks and in sight of the mountain runway at Alpe d'Huez.
Best flight ever and no problems of aggro from ATC.