If say the first tower nearest to the continent
isn't directly connected to the landmass.
Then, if by flight, or used as a boat,
they could get there to the starting point.
And the bridge is specfically designed
so that the modified FSD software can
identify the guidelines easily.
People can simply relax and choose
resting points as they go, and the software
will notify them if that particular tower
(resting point) is down for the moment.
And on arrival, they be given shelter,
following access to sustenance.
And be sorted out, checked of their background,
before entrance into the country.
So to be used as a "boat" is something to
design for Mr Musk. It would also
be an amphibious vehicle then.
At the resting stop,
there should be a space/another lane
in which the vehicle pulls away from the traffic.
Then from there, turned into the 4 wheeler,
or flight into the parking area.
Then entrance into the tower by walk.