As a former concierge in NYC and here in Orlando at Disney, it is best to order the flowers, basket, "goodies" and have them delivered after your arrival.
Cannot tell you how many times, we would put them in a preassigned room and they would disappear like a sock in the washing machine!
Believe it or not, rooms are pretty much assigned when you are physically at the front desk checking in.
If it is a special, huge occassion, like a proposal, call ahead and talk with the concierge, personally I have done things like hung up will you marry me signs with flowers and rose petals all over the room---but unfortunately, not every person goes this extra step.
Call WAY ahead of arrival and good luck!