All of these ideas seem WAY far for day trips and WAY many things to do in one day. At the very least, I would try to go to wherever-it-is the night before, so you can start early in the morning.

I would think that winter weather would be a pretty big factor in both Matsumoto and Yamadera--have you checked that out yet?

KYOTO: If you've been there before, I guess you know how far it is, but that's a lot of stuff for one day. Fushimi Inari Shrine really needs about 3 hours. It's a little short train ride to get there and back from Kyoto. The main part of the experience is hiking through the long paths of torii gates and you need to spend a chunk of time doing that to get the essence of that shrine. It takes about 2 hours to hike out to the far end where you get a view of kyoto. The rest of your itinerary can be a continuous walk except for getting to the beginning and back to the station, but it sounds like about 6 hours of time at least (and of course, there are heaps of stores and restaurants and little shrines all along the way).

MATSUMOTO: I think that Matsumoto is worth a whole day. To me, Nagano is more a place to go to other places from, although it's a nice city. The Matsumoto castle is quite nice--allow plenty of time. Matsumoto has a couple small historic areas, a great downtown shopping area, a big mall on the outskirts, and a lot of rather specialized museums and historic sites (such as a woodblock museum, a folkcraft museum, and one of the first elementary schools in Japan that's now a museum). You can also go from there to Narai, an old post town, by local train if you want something more than just one city for your day trip.

By the way, Matsumoto can be reached more quickly and MUCH more cheaply by bus--about 3 hours and 3900 yen with reserved seat. Buses are comfortable. They leave from the Shinjuku station area. There are 2 lines operating cooperatively (Keiho and ???) and they leave about every 20 minutes. (However, the last bus back to Tokyo is about 8 p.m., I think.)

SENDAI/YAMADERA--I haven't been to Yamadera, but it sounds like an all-day project, with the local train only running once an hour and all the climbing to get there. I guess it depends on how early you start but me, I wouldn't count on getting to the top by noon. (I'm going to put it on my "Next Time" list--it looks interesting.) Sendai's a nice "regular" city for shopping, eating, and night activities--it's not picturesque or tourist-oriented.