If you like to discover the enormous varieties of Cape Verde islands I encourage you to make “island hopping” mostly by plane.
Important to know is, that flights are almost in demand and an early booking is adviced ( the erlier the better).
Some destinations are rarely served ( i.e. to S. Nicolau).
A proposal is for instance to travel in a triangle (Sal-Santiago/Praia-S. Vicente ( and by boat to Santo Antão and back)-Sal.
Within that trip you can visit a so called “sandy island”(Sal), a mountainous island (Santiago) with the “heart” of Cape Verde (the capital Praia, included cultural locations like Cidade Velha)and São Vicente as a stopover (also with city of Cape Verde culture, Mindelo) and at last the impressive and spectacular island of Santo Antão (only reachable by boat)and from S. Vicente directly back by plane to Sal at the end of the journey.
This suggestion offers you three “holidays” in one holyday time. 😆