http://www.marsinstitute.info/rd/faculty/dportree/rtr/ma04.html

http://www.astronautix.com/craftfam/martions.htm

When I was a pre-teen I had the idea of a manned Mars mission using then-current hardware with the necessary modifications: Using the spare Skylab (beats having it sit in the Smithsonian collecting dust) and an Apollo CSM/LM. Two Saturn launches would place the entire setup into Earth orbit (maybe a third launch of a smaller rocket with the booster that would kick the Skylab-Apollo configuration to Mars if it could not be fitted with the Skylab itself).

The astronauts fly the combined Apollo CSM/LM to the Skylab (probably called Marslab at this point). The astronauts separate into the CSM and LM. They undock the two craft from each other and dock at the two docking ports on the station.

If the booster rocket has to be sent up separately from the Marslab, the astronauts might have to EVA to attach it to the station.

I also presumed the booster would be able to serve as a brake for the craft into Mars orbit and then bring the mission home when the astronauts returned from their surface explorations. I didn't think the astronauts would be very happy living in the confined space of an Apollo cabin for months, even if they left the LM ascent stage attached to serve as an extra room.

I knew even back then that NASA was abandonding its manned Moon and Mars plans. I hoped that if they could do something using what already existed, rather than start from scratch, it might have kept the dream alive, as it were.