There is no magical express to or from VB.
99.9% of people who have visited DVB would likely agree a car rental is almost madatory as the resort itself is somewhat remote from all other things in the Vero area.
To my knowledge, other than the rental you'd be looking at a towncar service or taxis.
HTH
editied to add, a few years back we had some friends staying with us in a beach cottage. they left before we did and we hired a local cab recommended by the front desk to take them to MCO. If memory serves me correctly, with a tip it was in the area of $200.