Best rail pass or buses?

Well I've been doing research into the various rail passes and buses available in Japan and while I've done my best to figure out, on my own, the best choices, my head is spinning just a bit.

I'd like some friendly advice on my best bets travel-wise. I'll be in Japan about two weeks.

I arrive in Tokyo in early June in the afternoon and I'll be going straight to Kyoto from there. I'll be staying around 3 days in Kyoto, likely taking the train at least one of those days to Osaka.

Then, I plan to travel even further south, to Fukuoka and spend another 2 or 3 days there before returning to Tokyo. I'll likely be spending the rest of my trip in Tokyo or no further than half an hour to an hour out by train.

Should I go for the super expensive 14 day rail pass or am I better off mixing certain train passes and buses. (I was thinking of doing an overnight bus from Fukuoka to Tokyo).

So basically, I must cross great distances, but will also be relying on local transportation.

Thank you very much in advance.

In your case, you will make your major trip within 7days(NRT to Kyoto to Fukuoka to Tokyo). So 7day Pass and SUICA card in Tokyo is better option.

I think it a better itinerary to stay in Kyoto longer, maybe for about 7days. But this is a matter of your preference.

NRT to Kyoto(staying for 7days visiting Osaka, Nara and Himeji)
Kyoto to Fukuoka(start using 7day Pass this timing)
Fukuoka to Tokyo to NRT.

Thank you for the possible itinerary. I'm curious if anyone else had any thoughts or advice?

If you do the round trip Tokyo-Fukuoka within 7 days, a 7-day Japan Rail Pass will be the best value. If you do it within 14 days, the 14-day Japan Rail Pass will pay off. For the rest, I also recommend a Suica prepaid card.