help with rail pass

Hi! with a wide range of local and regional rail pass available in japan, I am confused and unsure what would pay off for our planned trip this coming late april. Due to time constraints, we will only be visiting tokyo in 6 days from 25-30 of april. I know that would be too late for cherry blossoms in tokyo, but I read we can try visiting the northern part like Tohoku region. Now, please can you suggest a rail/bus pass for us to use in these areas and other else like hakone/kawaguchiko, nikko, and the areas with in tokyo? We are not just considering the time but the budget as well. Your help will be greatly appreciated. Thank you in advance.

You can probably use Tokyo Wide Pass. http://www.japan-guide.com/e/e2361_06.html
But it only valid for three days. So I would plan all your long travels during those three days.
Every thing else you can just buy Pasmo or Suica IC Card and load up as you need. http://www.japan-guide.com/e/e2359_003.html

Hope this helps!!
Have Fun!!