North Star Trekking and Gastineau Guiding have also been doing Mendenahall Treks... far longer than anyone else, I might add.
The "common" way of walking on the glaciers is via helicopter tour, otherwise you'll need a taxi or guide to get you to the trailhead on the West side of Mendenhall Lake (NOT where the visitor center is located...)
Either that, or come in the middle of winter when the lake is frozen and explore all you want!
The only way to keep everyone happy is to delete my signature completely.
If anyone wants advice from a life-long Alaskan resident, please don't hesitate to ask.