If Cuba built its own onion routing network (perhaps using Tor software though not connected to the Tor network), then each satellite dish or other internet connection would automatically be able to facilitate connectivity for the rest of the network. No need to wire anything (except some of the exit nodes), this can all happen over wifi.
Don't forget that 802.11af, 802.11y, and 802.22 have ranges measured in miles (802.22 can cover 100km). Blanketing an island of 110km would still take a good number of antennae (especially given the dead zones created by dense buildings in cities), but at a governmental budget scale, it seems quite feasible.