Thanks Guys
MMM - Maybe 3 weeks is too long, I think 10-14 days may be better because I want more than a week.
filiadragongurl - Is this the hotel you stayed at
Hotel Raizan Kitakan ? Does seem decent and well priced (under £90 for 10 nights) Is Osaka far from the centre of Tokyo and is it easy to travel to Shinjuku from Osaka?
thanks all