In reply to Removed User:
Hi Eric!
It's described in the SMC Highland Scrambles North guide: basically avoid the lowest wet rocks on the left, then gain the ridge with a couple of scrambly steps (Grade 1 or 2 depending on choice of line), then boulders to the top.
From RSM you can either descend into Coire Mhic Fhearchair and follow the path round (there is a reasonable descent mostly on grass from about 500m S of the summit, saves going all the way to the col), or else go over the ridge: there is a lot of vile scree on the south side and it may be worth worth ascending the first shoulder towards Spidean Coire nan Clach and dropping into Coire nan Clach, which avoids it all.