Go to Mars on a Bigelow spacehab

Way speculative post here, so be forewarned.  This is a quickie post and I don't have access to my spreadsheet at the moment.

Anyway, it'll be on a BA-2100 to be exact.

Here's how to do it.  Launch the space hab with a big ass rocket like the fully tricked out SLS.  Or you could use a SpaceX big ass rocket Musk is talking about that could lift 220k lbs or more into orbit.  Going along for the ride will be a VASIMR propulsion system.  These two will dock and then the VASIMR will tow the sucker on out to the EML-2 Lagrange point.  A second big ass rocket will do the same trick, but this time with a propulsion system for the trip to Mars, with some supplies.  The propulsion system would be like the SIVB of the Apollo days in terms of weight and so forth.  You could add a system that will make fuel on Mars with its lander. The third launch will take a crew directly to EML-2 where they will rendezvous, and then take off for Deimos.  The third launch could also be a big ass rocket that would carry everything the first two didn't.

All of this would work better with a NTR, but even a Methane/Lox system might work.  With an NTR, you may even put mining equipment on Deimos in advance of a trip back home.  Half the crew would be working up on Deimos setting up the mining equipment.  The other half would be on the surface of Mars setting up mining equipment for the trip back to Deimos and the way home.

The BA 2100 will hold up to 16 crewmembers.  You could pare that down, if that's too many.