In all the years I've monitored trip reports, I have never seen anyone write of crossing that ridge. It sure look impassable from either side -- lots of near vertical granite. You CAN go from lower Boy Scout over to Mirror Lk via Thor Peak, but it's a hefty climb in itself, and then you'd need to head back up the canyon to retrieve your gear.
It has always been my experience that if you can climb something safely, that you can also descend it. It just takes more care.
Guide services go up the MR that time of year, and they always rope up their clients and both climb and descend that way.
If you go in April/May, you should find conditions good for crampons and an ice axe. However, if you encounter rock-hard ice that you can't get past, I would say turn around, don't even go up!
Good luck!!
I’ve done it before Steve. It’s definitely not going to be easy to cross that ridge to get back to the North Fork. Far better to descend the MR.
https://cdn-files.apstatic.com/climb/110674689_large_1494342759.jpg
