Rail travel in Japan - Are commuter passes valid for travel in both directions or only one direction?

♡Yes, ↑that's right.
I second that.(*^o^*)
My hubby and I both just get ONE pass.
It goes BOTH ways!♡
～☆We might pass each other in Shinjuku!(*^o^*)

Yes it works both ways, but why are you talking about the price?
If you work for a company, they should pay for the pass. I lived in Tokyo for 9 years and I never paid even 1 Yen to commute.

You only need one pass. And, of course, you can use your pass to get off in between (as much as you like) Hachioji and Shinjuku as it covers every stop between the two stations.

One pass is good both ways.

It is not a problem, other than maybe inside the train stations and getting to the right track with the stroller. Most of the larger stations have elevators. I travel using the JR Rail pass, and it is great! Yes, it will be good until the end of the day on the Sunday you mentioned. There are no special train cars for children. I always upgrade and get the "Green Car" pass. As far as the stroller and luggage, you can put those behind the last row of seats in the car you ride in. Smaller items can go up over your head. I would recommend a small stroller! There is not that much room, and the storage is first come, first served. As far as hotels, I normally stay in very nice ones. Most cities have decent hotels right by (or attached to) the train station. Nagoya Station has a great Marriott ($130). Kyoto Station has Hotel Granvia ($190). Tokyo is a lot more difficult, because it depends what part of the city you stay in. I normally stay in Shinjuku, at the Century Hyatt ($225). For sight-seeing, most hotels offer bus tour packages, which I highly recommend. I've done them in many Asian cities, and they are safe and informative. You may also want to go to Hiroshima and tour the "Peace Museum," which is all about the atomic bomb dropping. It is a quite humbling experience for an American! You will see a lot of the countryside just traveling on the trains, although it goes by fast. I hope that helps!