[Big Jim]

Does anyone have any recommendations on the best way to purchase tickets for 3 weeks? We would want Disney, Universal, SeaWorld, Busch. We've done the big 'all-rounder' one in the past but it only covers 14 days. I'm thinking along the lines of 14 days Disney/14 days for the others so that we can access parks from day 1 to day 21 if that makes sense (?) with an overlap in the middle week but it seems so excessive. We'd only do Busch and SeaWorld once.
My brain just boggles looking at all the various combinations!