Travel question Fukuoka to Tokyo

Hello,
I am arriving into Fukuoka by ferry and would like to visit Hiroshima, Kyoto and Tokyo (where I will be flying out of Japan from) I will be arriving on a Weds evening and leaving Tokyo on the following Tues morning - so it's less than a week.
Is is still worth getting the JR Pass? As I don't have much time, I don't want to spend too long travelling between places (or taking buses) so I'm wondering if the JR Pass is better value even though I won't be using the full 7 days, or whether I should just get single journey train tickets - I've heard these are pretty expensive though?
Thanks for any help/advice you can give!

The pass shouldn't be considered on the "days" aspect as much as how much the total of your fares is in the same period. If the total of your trips costs more than 28,300 and you'll be there less than 7 days, then it's worth it.

Use http://www.hyperdia.com to check for ticket prices, remembering to look at the "total" of the fare at the top of each option. Plug in the stations and add the totals. You can't use Mizuho or Nozomi services, so "untick" that option in the option screen. And also remember that Fukuoka's station is HAKATA and not Fukuoka.

It would be worth it, but not by a huge amount. It does also save you some time having to buy tickets also. If you add in a side trip to Nara,
and include taking the Narita Express, you do in fact recoup the costs.
As for what you want to see, that is up to you. For Fukuoka, there is a good guide to cheaper accommodations and places to see at:
http://www.tinyurl.com/see-fukuoka
For Hiroshima, you can see the city in a day. You didn't say if you want to see Miyajima, but it's worth considering. Look at:
http://visithiroshima.net
Kyoto/Nara are the cultural jewels of the country and worth at least half your time in Japan. See
http://www.pref.kyoto.jp/visitkyoto/en/
http://www.kyoto.travel/
http://www.ar.jal.com/world/en/guidetojapan/city_information/uky/see/c...
http://www.pref.nara.jp/secure/79931/yukari_usa.pdf
Finally, Tokyo can be a fun place but just pick what really interests you. See:
http://www.gotokyo.org/en/index.html
http://www.jnto.go.jp/eng/location/regional/tokyo/index.html
http://www.ar.jal.com/world/en/guidetojapan/city_information/tyo/see/a...

Thanks very much for your help - I was having trouble using the train website as I was putting in Fukuoka as my start station so was getting strange results, so thank you for clearing that up!
And thanks for the tip about Hiroshima, I was thinking of spending 2 days, 1 night there but if it can be done in a day, then it means I can spend more time in Kyoto/elsewhere.
Thanks for all the links too - very helpful!