I made this amphibious aircraft which can carry 6 passengers. Although it isn't exactly an "amphibious rover", it can travel on land and it is amphibious. As a result it doesn't look very good, but it flies surprisingly well. Whatever you do, don't turn on SAS. For some reason, this aircraft will vigorously roll to one side for no reason if SAS is enabled.
It would barely fit in the cargo bay, but with the landing gear retracted it might be better at doing so.
"Driving" around the KSC to show the "off-road" capabilities.
Taking off from the grass.
Flying around the KSC.
Landing in the sea near the KSC.
Did I mention it can also go underwater?
Not for long though.
Taking off in the water is slightly harder than usual.
This is why the aircraft has a pair of wings under the main set of wings. It needs to use those lower wings as a hydrofoil in order to accelerate to takeoff speed.
Taking off from the water.
Returning to the KSC.
I almost crashed into the ground in order to take a screenshot of it on final approach.
Slowing down to a stop.
Everything appears to be intact.