Cheap - good - easy --- pick any two.
Cruise terminal - good and easy.
Offsite parking - cheap and good.
Recommend you look into: Go Port 3345 N Courtenay Pkwy, Merritt Island, FL 32953
If you are platinum/diamond or otherwise have priority disembark, then you shouldn't have any issues getting back to Go Port after the cruise because you'll be on one of the first shuttles back. JMO...