That's pretty much right tonyted.
Anybody who's spent that long in space has taken a quite a long time to recuperate although ther's been some success with excercise on bungee ropes
The radiation issue comes about because you'd be well away from the Earths magnetic field so if you get caught in open space after a solar flare you could get a nasty dose of radiation - that's not so tough you turn the spacecraft to put it between your kliving quarters and the sun but micrometeorites will still do a lot of damage over a year out and a year back and there's no repair facilities on mars.
Then if you want to land you have to create a craft capable of landing and getting back out of mars' gravity - it's a lot stronger than the moon!
All in all it's a pretty tough set of requirements. Not impossible but you'd want a pretty good reason for doing it. I'm not convinced that right now that reason exists.
Of course should one of those little robots turn up a fossil that'd be different :c)