Japan is a large, diverse country. You could easily spend a lot of time there. If you're going for only a week, you might want to stay entirely in the Tokyo area. (A week isn't very long considering how much time you're going to be spending travelling to and from Japan.) If you're going for at least 10 days, I recommend venturing out to Kyoto and other cities. There's downhill skiing in the Japanese Alps and the north, but Okinawa is like Hawaii -- you can pick your weather! Tokyo is unique and very dense. Comparing Tokyo to other Japanese cities is like comparing Manhattan to any other american city.
Tokyo Disney Resort
The parks are easily accessible by train. If staying at a Disney Resort or a Good Neighbour Hotel is prohibitively expensive, don't hesitate to stay in a less expensive hotel and take the train to and from the parks. (Allow 30-60 minutes travel time, depending on where you stay.)
I recommend spending 4 days in the parks, if possible. You can do it in 3 days, but it may be rushed.
English-only tourism?
No problem, especially in the cities, and theme parks. Cast members are especially helpful, and if they can't explain something, they will either lend you a written card with English instructions ("How to ride Dumbo") or lead you to where you need to go (child swap "switchy" on Big Thunder Mountain - Japanese speakers were given instructions to talk to a cast member at the ride exit, English speakers were told "this way please" and personally escorted through the cast-member only corridors and directly onto the loading platform).
Food language barriers
The only challenge may be with the food. Food service providers may not speak English, but almost every restaurant has a display of plastic food, and you can order just by pointing. Many places will have signage written in Japanese and English pronounciation, but not necessarily the English translation. For example, many restaurants will have a Japanese label, followed by "Tonkatsu", but you'll need a phrase book to see that means deep fried pork cutlet (like schnitzel, only better).
Phrase books?
Get one, but not a bulky one. I like the ones published by
Frommers or
Lonely Planet. These are extremely useful for understanding everyday situations involving food and transportation, as well as unique situations where a translation tool is essential, like a hospital emergency room.
Isn't it hard to speak Japanese?
It's hard to read Japanese, especially since most words have a unique character (there are 1000s of characters). However, all Japanese words can also be written in katakana script, which is a way to pronounce each spoken syllable. There are only 46 katakana characters. These sounds are often written in English, and they are not very hard for an English-speaking tourist to pronounce. Virtually sounds all end in a vowel. "Mickey" is easy for Japanese, but other Disney character names are slightly modified, like "Stitche" and "Donaldo". Many Japanese words were adopted into English, like karaoke, sushi, tsunami, teriaki, tempura. Similarly, many Japanese words have English origins, like milke, baby-ka (stroller), baby-seato (high chair).
Some common phrases are pretty easy. Like "______ wa do-ku des ka?" Which literally translates to "________: Where is it?" Examples: Toyre (toilet) wa doku des ka? Mickey wa doku des ka? Sushi wa doku des ka?
Money, money, money...
The exchange rates are always changing, but a general rule-of-thum is 100¥ = $1 US. And yes, you can find 100¥ stores full of knick-knacks in most Japanese cities. Cheap gifts for friends and family back home -- it will be our little secret.