There were multiple mentions of the future ideal first stage ASDS landings - if the mission won't have enough deltaV to do a RTLS, then just land on the barge, refuel and "hop" back to the launch site.
How much fuel is needed for such a hop and how can it be done? Would it be most effective to go "back" to space and endure a "full" reentry and landing again? Or might it be possible to return through atmospheric-only flight (I am thinking about multiple engine ignitions maybe)?
Would it make any sense to fill the first stage full of fuel to work as ballast and allow hover or would it burn most of it anyway to get to the destination (rocket equation is such a tyrant)?