We did the same plan you're doing and had the 4-park flex ticket offered through our 7-day US Vacations pkg. When I booked the vacation, I didn't realize that DC gave a 7-day admission to SW for free......and now that is offered as a choice of SW or Busch Gardens for 7 days. We did Wet n' Wild, but if you've been to other water parks around your area, this one is nothing that special...we spent from about 10 am until 3pm and our 17 and 14 yr. olds got bored and frustrated with the long lines for everything. There were not nearly enough park "free" tubes for the pool, lazy river, etc. , but they had stacks and stacks of them for a rental fee....nice little business. You also rent lockers, towels, etc. PLUS, they charge a deposit fee for all the rentals! It doesn't leave a lot of lunch/snack $$ available. We are planning our next July vacation, but I will opt for US/IOA/City Walk passes, DC (and if SW or BG is still included, we'll do them) Depending on when your DC visit is planned, the 5 day US/IOA pass MIGHT work best, but I think it has to be 5 CONSECUTIVE days? and if your DC day was in the middle of that, like ours was, then you would lose one of those days.