You never know until you make the call. You may be disappointed but you may be pleasantly surprised with an avail!
Orlando and West Palm Beach are the two main airport choices. WPB is slightly closer and more direct than Orlando but not that big of a difference (especially if you can't resist stopping by WDW on the trip as well). Melbourne Airport is actually the very closest to Vero but does not always have direct service from many destinations.
The drive from MCO, depending upon how fast you will go and traffic, is about 1 1/2-2 hours. Most of the drive is taking the Beeline across and then I-95 down through area that is/was ranchland. Best to make a pit stop before heading out.
Good luck with reservations!