I'd go in a skinny minute.
As far as what to do? Hopefully, the ship would be at least as large as a couple ISS modules. In fact, I prefer that we look at modular design for my Mars Trip. I'd like to see 2 or 3 fairly "spacious" modules boosted into LEO by th eless expensive non man-rated boosters and assembled in orbit.
Then me, my guitar, my PS2, a high-end laptop and a couple of extra removable 1TB HD's full of games and Wiki and mp3's and everything else you can download onto 2 or 3 TB can hop on board for the transit. Of course, if room allowed, one could also have a nice rig with a full ATX tower and 4 2TB HD's.
Once there, I should hope that I had a little Hab or 3, perhaps inflatable like Bigelows, and the equipment and supplies to do meaningful hydroponic gardening, and also the ability to go outside and explore and collect samples to test in a lab as minimal as possible without compromising diversity of testing.
That and a Comsat in Geostationary orbit with some decent bandwidth for communication. I'd stay 5 years without blinking. In fact, I wouldn't want to spend all that transit time for boots and a flag and then an immediate ride home.