Come back? This was the era of disposable launchers - you launch a huge rocket and get back a tiny crew capsule, with everything else abandoned in stages along the way.
The original Saturn V could lift 118 tonnes to LEO. The upgraded Saturn V (used for the last 3 Apollo missions) could lift 140 tonnes to LEO. If they’d kept making and using the booster, there probably could have been a couple more upgrades. Nasa did several paper studies in the 60’s of beyond the moon missions using Saturn V launchers. Quite a few involved replacing the Saturn’s third stage with a nuclear thermal rocket to provide the extra oomph needed.
One involved only a single Saturn V launch, with a nuclear thermal rocket upper stage, total mass to be lifted to LEO, 118 tons. As they got close to Mars, the astronauts would get into a lander, dash ahead of the main vehicle, land on Mars, spend 9 days doing stuff, then launch back up and meet with the main vehicle as it looped around Mars before returning to Earth. Not putting the main vehicle in Mars orbit saved a ton of fuel and obviated the need to do multiple launches.
Another envisioned a similar flyby-without-orbiting mission, with loads of robotic probes and at least one robotic sample return but no manned landing on Mars. It would have required four Saturn V launches and if I read it right, no nuclear upper stage (which gives you an idea of the vast benefit of using nuclear rockets over chemical rockets). It was envisioned as the first step toward a later, larger expedition that would land astronauts on Mars.
Both of these were basically six months to mars, 18 months back to Earth missions.
Finally, here’s a full up mission to enter Mars orbit, land, and return with a lot of rock samples. Total amount to be lifted to LEO, 2,100 tonnes, fifteen Saturn V launches, most of them with a cargo of nothing but fuel. On the upside, total mission time is cut to fifteen months.
eta: the plan involved using a stretched Saturn V with strap on boosters, capable of lifting 250 tons to LEO, so you only need nine launches.
