I'we done a lot of Mun exploration on my campaign lately. Here's what I ultimately came up with...
A very Apollo like CSM with a capability to fully RCS translate after SM jettison. A lander with a compact rover on the bottom and an ascent stage + a habitation module on it's "deck" for an extended stay on the Mun. Both have Delta-V to spare so the lander can be hopped if necessary.
The Lander's docking port is not on the center line of the combination so a gimbaling CSM main engine and a bit of RCS is required to balance this during the MOI maneuver.
PDI. The lander has 4 Twitch engines clustered around the lander which have plenty of power for the job. The lander is somewhat top heavy because of the added mass of the hab but nothing that the engines, a small reaction wheel in the ascend stage and little RCS can't handle.
Landed safely. The crew is heading out to do stuff in their sporty rover.
Time to head home. The ascent stage lifts off from the deck of the lander for a rendezvous with the CSM. The landing stage could be used as a place of refuge and a fuel reserve for later missions in the same area.
-MiikkY
