A few notes about things I do when I travel to Japan.
I travel with a carry-onable back pack. Anything larger would be obnoxious when negotiating trains/bus stations. Specifically, I travel with an Osprey Porter 46. Even with that, I usually plan my day around dropping it off as quickly as possible (even if it's prior to check-in, hotels will always hold it for you). If you ever need to ditch your bag, search any major train station for coin lockers large enough to cram it in (coin lockers are typically deceptively deep and spacious).
Plan on carrying plenty of cash. Many Japanese don't own a debit/credit card, and using them is usually mildly onerous as a result. Chains and major retail outlets will accept credit, but many small & local establishments won't. Personally, I always withdraw a few thousand bucks US and take it with me on a money belt on the plane. Once you arrive at the airport, there will always be a currency exchange near the exit from customs. (Because their surcharge is baked into the rate, I recommend changing only some money at a time so you don't have to change a lot back into dollars for a loss later). Once you're in the country, the best place to change is at a Japanese post office (you'll stumble over them often--look for the 〒 symbol on signs or ask ”郵便局はどこですか？” (phoenetically: 'you-bean-kyoku wa doko dess ka?')
Keep your passport on you at all times and make yourself scarce if you witness anything like a bar fight when you're out at night. Counter to common wisdom which might tell you to keep your passport safely stowed away in your room, Japanese law stipulates that you must have it on you as evidence that you're in the country legally 24/7. If you're ever stopped by police, presenting a passport and saying thanks in English will often be sufficient to conclude the conversation. If they happen to stop you without your passport and things go south, they're legally empowered to detain you for something insane like 23 days without cause.
We always purchase Japan Rail Passes. Acquiring these is confusing but not difficult.
Passes can't be purchased by Japanese nationals and they must be paid for outside the country. What you purchase (again, while still in America) is a notarized exchange voucher from a travel agency. Once you arrive in Japan, find the first Japan Rail (JR) office and exchange the voucher for a rail pass there. They're not cheap ($400 or so per person for a 14 day ticket), but if you plan on riding any bullet trains (as you ought to if you're going from Tokyo to Kyoto and Osaka and back), it'll almost certainly pay for itself. Simply present it (displaying the expiration date outwardly) at any JR turnstile to an attendant and they'll wave you through. It works for the bullet trains, but not for reserved cars or for the fancy "Nozomi" line (you can usually weed those out with English signage). Also, don't bother buying the expensive Green one, as few trains you ride will feature green cars.
Note also that a Rail Pass won't cover every train in the country, and it usually won't cover bus fare. Virtually any Japanese tourist agency office can sell you one on the spot, but bring your passport and make sure the name matches the passport exactly. (I had to beg and plead that "Becky" and "Rebecca" were equivalent a few years back). More details here: http://www.japan-guide.com/e/e2361.html
If you don't get a rail pass or if you're riding a private rail line (or subway or bus), most ticket centers have at least one terminal that'll have an english button somewhere on it. When you're in Osaka/Kyoto, someone will probably offer to help you, because unlike in Tokyo, people are typically nice and gregarious.
The procedure is usually something like:
- Look at the huge printed map for your destination and find out how many yen the ticket costs (labeled by the station name)
- Enter enough cash into the machine
- Select the value you know you need
The train schedules are usually very readable and clear, both the LCD headers and the printouts of the line that you're on. However, it can be tricky to figure out exactly when to change trains -- particularly between an express and a commuter train to get to a specific destination. I'd recommend (and this app requires internet access, sadly) the Hyperdia iPhone app for figuring out any complex train itineraries.
As a last resort, just ask. Typically, if you ask a JR employee "I want to go to ___" and look confused enough, they'll stay with you as long as necessary to help you out. If you're on a train and need to know if the station you're arriving at is your exit (or change), just point at the door and ask the name of your destination to literally anyone around you.
Because they're too big, we only travel with iPhones, no laptops or tablets. Next time we might try to squeeze a mini but I doubt we would.
If you're leaving so soon, your options are somewhat limited for attaining mobile internet access.
You can, of course, call your phone's provider and buy an international data package for some sum of money (and do your best to stay on airplane mode during most of your trip to budget it appropriately).
However, it's usually more convenient and economical to rent a SIM or device from a rental service. Alas, the only services I'm familiar with require significant lead time to ship a SIM card or a mobile hotspot to greet you at the airport. If you're interested, last time we rented a 3G DOCOMO mobile hotspot from a service called Pupuru.
Most hotels will give free Internet access over ethernet but do not have wifi service. This is a dilemma if you only have a smartphone. What I did was buy a $99 Airport Express, configure it at home before I left, and then just plugged it into the free ethernet port. This worked very well in every hotel we've stayed at (probably 12 or 15 in the two trips). Typically, we use the hotel as a base of operations to (a) upload pictures, (b) book our next hotel room, and (c) search for local things to do or train schedules.
These usually charge by the hour and give you access to desktop computers with broadband access as well as hot ethernet cables. The only downside is that you're probably going to need to play trial-and-error to figure out how to type english on a Japanese keyboard. (Hunt for the character 英 along the top/bottom/left). Somewhat surprisingly, internet cafes never seem to offer wifi.
Aside from our first night (which we book in advance; Japanese customs requires you to provide an address of where you're initially staying), we book hotel rooms from our iPhones, usually the same day or a day ahead, so we can explore more freely.
The single best site for short-term online hotel purchasing that we know of is JALAN's english site. It's totally separate from the Japanese-language site, and they filter results down to just hotels that certify they can speak english with you. Simply pick the city (or the prefecture/state) you want a room in, and follow the (somewhat weird and asanine) instructions. Most hotels will have you pay in-person, but some will let you pay with a CC online. To reduce fraud in the case of the former, they send a goofy email verification halfway through the reservation process that you have to receive and click before you complete the booking.
If you're in a jam and don't find a place to stay, you can always attempt to use Expedia / Orbitz / Travelocity / Hotels.com, but I've noticed that prices and selection on those are usually not great. You can always just keep walking until you find a hotel and ask the front desk if there are rooms.
As a very last resort, most Internet / Manga cafes are 24 hours, have lockers, couches, and showers. I've never needed to, but I've used sleeping at an Internet cafe as my backup plan on numerous nights out. It's probably cheaper than most hotels will be, too.