"Next time a man lands on the moon,
he must check whether a kerbal needs a rescue mission"
Last stage with RCS engine provide more than 1000 m/s of delta-v. Enough to reach Mun or Minmus.
As usual ; less 30 parts, early technologies, low cost.
Standardized protective shell to include early DMagic parts (see pictures below as examples).
If you add parts, be cautious to keep CoM well balanced (RCS Build Aid mod would help you)
|Mass||9.606 t (dry: 3.366 t, fuel: 6.239 t)|
|Ressources||ElectricCharge, MonoPropellant, LiquidFuel, Oxidizer|