By every account I've heard, keeping the ISS going is seriously laborious for its crew. And both astronauts have previously done regular ISS missions, to quickly get back up to speed.
If anything, the extra couple people on board is a great help for stationkeeping and workload division to help give everyone a break.
I'd bet there's always some set of experiments queued up, maintenance, etc.
I believe there's always a backlog of science experiments to perform.