This thing is going to be as big a flop as the C-47 on floats and for the same reasons (hard to service, hard to load/unload), unless all the USAF plans on putting in it is "self loading cargo".
If they insisted on using the C-130 platform they should have gone back and looked at the Lockheed proposal from 1960s/70s that used a bolt on hull/hydroski arrangement and was flight tested with a large scale RC model. They even put out a 60+ page prospectus on it (I have a copy). They used fiberglass back then, now with modern carbonfibers it would be lighter and stronger.