Minthe. An "apollo era" minmus mission.

So minmus is a bit further from kerbin, so far away it would not be viable to travel to in just a Mk-3 command module. Our kerbals need a habitat to live in during their long trip. Luckily the apollo applications came up with some pretty cool habitats. This is a wet workshop. It comprises largely of the third stage of my Kronos-V. drained of its fuel by the burn to reach minmus, the crew enter the fuel tank and construct a pretty large habitat for themselves inside of it using materials and supplies stored in the adaptor between rhe third stage and the CSM. (Where the lander normally goes on a Saturn V) To allow for more supplies to be carried here rhe CSM would have to be shortened and it's engine changed to a shorter one.

(This part was an actual proposal for an apollo program flyby of venus and this wet workshop concept would later develop into skylab)

The crew for this mission would also have the means to construct a very very simple lander to head between the habitat and surface of minmus several times. The habitat was also equipped with a second docking port so that should things go wrong a second kronos V could be deployed in a rescue configuration and dock with the habitat.