Thanks so much Steve. Love this forum.

I called and the person I talked to didn't think it would be a problem, and to leave a copy my permit (or permit reservation ) on view along with a note "JMT hiker ETA"... She said to park along the side of the road which I gather, from an annotated overhear photo I found somewhere on the forum, is the drive up before we'd reach the parking proper.

I'm still concerned about spaces available on a weekend, although that's good to know it's possible.

Thanks for the suggestion re: Mammoth. I'm still really struggling to figure out how to get up to to Yosemite after I leave the car. I'd bus it but that ESTA doesn't run on weekends.