Reviving an oldish thread here. I'm the OP. My wife has done the trip several times now. Always, Shin-Osaka to Shinagawa, transfer and to go Ikebukero, transfer and go to Tokorozawa. After the medical appointment, she does the same in reverse. Not bad, but requires two transfers at large, crowded stations in Tokyo. Would like to fine an easier way.
I checked out the idea of transferring at Odawara and then on to Tokorozawa. However, to stay on the same shinkansen train, she needs to catch a Hikari that leaves Shin-Osaka at 8:13am, which is too late. She needs to arrive in Tokorozawa by about 10:00am.
I thought that I'd post one more time to see if there may be other alternatives. My main goal is the easiest method, as her condition is not great.