Grinnell can be climbed directly from fish Creek saddle. From dry lake, the use trail up past lodgepole spring is steep but easy. Lake peak is by far a better summit tho, so do it instead or both. A slope of Grinnell was reported to have a cannabis grow with hostile growers last year. I believe it was an eastern slope. I never read of a resolution to that, so use caution from the fish Creek side. This was discussed in this forum.