Looks like a nice itinerary to me, not over stuffed with plenty of wiggle room.

The concern I have is the Sunday May 20 Mitake San hike. We joined my father-in-law during Spring 2016 for a walk along the beautiful gorge starting at Hatonosu station. Only problem was that parts of the trail had been closed following the 2011 Touhoku Earthquake which meant long (and unexpected) slogs along busy highways with no pedestrian areas. We had a very wriggly 6 year old with us and the highway parts were extremely unpleasant (didn't help that her super power energy levels were drained whenever there was no dirt under her feet - almost as if tarmac was kryptonite).
There was very little information about the closures and detours, and I don't know how I would have managed it at all if I had been travelling without Japanese speakers/readers.
When doing your research for the trail you choose, do please make sure that the information is recent and has been conscientiously updated if it is not.

In our case, we ended up having to find and take a taxi to get to a station. Be careful also to have the timetables to hand for the trains as the routes are not very regular. I believe you'll have a few faster trains that are laid on on the weekends to make the journey easier. Be sure not to miss them. (We also had an hour or so delay on our week day return to Tokyo - there was something wrong with the power cables, ended up being a rather long day. Very pleased we didn't have a restaurant to go to afterwards!)