The tension between setting out a positive agenda for governing and the pressure to continue to block and obstruct will be very, very high.
With the exception of a reconciliation package that can be done with 51 votes in the Senate, everything else will take 60 votes to overcome filibusters (I am assuming that McConnell, burning with indignation at the Harry Reid-led Senate, will not degrade it further by his own filibuster nuclear option). Perhaps there will be a few cases—say, a single-shot repeal of the medical-device tax, a bill to force approval of Keystone—where he can find a bipartisan majority and maybe avoid a filibuster, only to end up with a veto.
Budget reconciliation—used by George W. Bush and congressional Republicans for his tax cuts, among other controversial policies, and by President Obama and Democrats for the Affordable Care Act—is a potentially powerful weapon that can encompass substantive policy changes under a budget rubric. But even getting 51 votes for something that will satisfy a majority of House Republicans, which will itself be quite hard-edged and radical, will not be easy. It will take winning over Susan Collins and a slew of Republican senators up in 2016, including many in blue states. Among them: Kelly Ayotte, Pat Toomey, Dan Coats, Lisa Murkowski, Roy Blunt, and Mark Kirk.