Between flying to the moon and back (no landing) the only difference is fuel and consumables (air/food). The key capabilities are launch, landing, spacecraft communication and operations, and navigational support for computing and executing maneuvers to get into (and out of) a trans-lunar orbit. The more fuel you have the easier it is on the equipment.

Or to put it differently, the difference is that when you get to the Moon you make an orbital injection burn in order to slow yourself down to the point that you can stay in lunar orbit, and then when your done you make another burn to put you back into the trans-lunar orbit.

When you get back you can either do a high speed re-entry or you can do an Earth orbit injection burn.

You still need a vehicle that can carry people for the duration of the trip. You need to get it into a translunar orbit so that you can get out to the Moon. You need to be able to precisely locate yourself in space relative to the Earth-Moon system and course correct to achieve your orbit goals. All of that stuff has to happen either way.

There is an excellent discussion of the various orbit options for getting to the moon in this paper: http://www.esa.int/esapub/bulletin/bullet103/biesbroek103.pd... definitely worth looking over to get a better appreciation on what is involved.