I agree that there's not much point in trying to learn spoken Japanese unless you are really serious about it. There are few really fluent English speakers here, but pretty much everyone knows basic words and phrases in English.
The bigger hurdle for foreign visitors, IMO, is that you won't be able to read anything unless it was specifically translated into English. So one thing you might consider is trying to learn some Japanese characters, which is not as insane as it sounds.
If you can memorize most of the katakana (there are 46 of them, each representing a syllable), you will be able to phonetically read any foreign loanwords written in Japanese on menus, signs, etc. There are a bunch of websites and mobile apps that you can use for this purpose, e.g.
http://quizlet.com/47772/katakana-practice-flash-cards/ I managed to cram all of the katakana over the course of a few days when I was taking Japanese in high school, using a combination of silly mnemonics and self-quizzing, but YMMV.
If you have enough of an attention span for it, you might want to also learn some basic Chinese characters. Even if you just memorize the English meanings of a few of them you will be surprised at how much text you can decipher in Japan. This is doubly helpful if you plan to visit China as the characters used there are very similar (sometimes identical). The first-grade reading list is a good start:
http://www.learn-japanese.info/firstgradekanji.html
I wouldn't bother to memorize the Japanese pronunciations, because (a) there are several for each character and the appropriate one depends on context, and (b) as a newbie you will probably not get the pronunciation right anyway.