- Most bank ATMs in Japan now accept foreign cards.
- Credit card acceptance remains low by international standards, although things have improved a bit with the "cashless" drive. Carry cash (yen), you'll need it at many restaurants and even some hotels.
- Most rail companies now sell discounted advance fares and LCC airlines are competitive as well, so a Japan Rail Pass is no longer the no-brainer it used to be, although it's still a good deal if you plan to travel a lot by train (say, Tokyo-Hiroshima and back).
- Instead of calling hotels, which will be a struggle because they often won't speak much English, use Japanese booking sites like Rakuten or Jalan.net, which have thorough coverage, the best rates and functional English interfaces.
Have a read through https://en.wikivoyage.org/wiki/Japan, it goes into too much detail at times but is a pretty good primer for all the things in Japan.
I've been to Japan tens of times for work, family and holiday reasons, and I've never found a use case where the JR pass would have paid off for me. Then again, I tend to fly in and stick with a single region; if you're doing the tourist trail thing where you're going (eg.) Tokyo-Kyoto-Himeji-Hiroshima-Tokyo in a straight line in one week, than sure, it makes sense.
I really recommend doing the math based on your particular itinerary. I've been to Japan twice, 14 days each time, and, at best, I would have broken even on a JR rail pass based on the traveling did. For longer trips, like Tokyo <-> Sapporo airplanes are both quicker and cheaper.
And it's not like you have to get the pass for all region, there are dozens of types of regional jr passes depending on the region you're visiting. Those are the ones that's of better value when travelling in-region, and covers most touristy places. Personally I'd say tokyo-wide, kaisai, and hokkaido are the ones that's pretty no-brainer when in those regions.
However, if you wanted to take a 1 year sabbatical, you could get a job as an engineer with a Japanese company, work for a year, apply for fast track permanent residency at the end of that year (you’ll need to meet some education/income requirements), then go back to your old job remotely. There are software jobs that hire people who don’t speak Japanese.
NO.
You must have a work visa to live here, and you won't get that unless a Japanese company sponsors your visa. A US company can't do that for obvious reasons, unless it's a company with a Japanese branch office.
The only way to do what you ask is to get permanent residence first, but that means living here for a while on a work visa or spouse visa.
Also, on top of this, the US company may have issues with you living outside the US while working for them, but that'll be the case for any other country. This was discussed within the last week or so here on HN.
I also pretty much exclusively have software experience in government contracting so the jump to commercial would be pretty big too.
Or you can work at an American company like Google (not sure if they're still hiring though; I thought I read they had a company-wide hiring freeze).
I am not trying to discourage you, but if you really want to live in Japan, you have to learn Japanese, which is not an easy language to learn, especially for English speakers, even if you live in Tokyo.
edit: wording
I am going next month, the Japan Rail pass sounds like a big saving, can I also use Shinkansen trains with the Rail Pass? Specifically the Tokyo to Kyoto route (JR central)?
Also, if you're just going to Kyoto from Tokyo, it really is not worth it to get the pass. Just buy regular tickets. The pass is useful if you're doing a lot of train travel in a short time.