We've got a foursome for 6/16-17 and seem to be in a similar situation regarding experience. We are guys, late 50's early 60's. Kinda antsy 'bout the snow/ice. Willing to give it a shot, but prepared to turn around if it exceeds our capabilities. We are getting mixed signals about ease of use of in-step crampons on the main trail. One experienced person I trust indicates it is slow but do-able, the ice should only be on the switchbacks.
We are planning on acclimating at Mammoth with a few rounds of golf, and a bunch of carbs. (could be skiing there instead).
See you on the trail