The easiest would be to post screenshots, but I don't have a way to upload them. I guess at some point I should get an imgur account or something.
You want the lander to be as light as possible, because to reuse it and/or hop around you want it to take as little fuel as you can (so that the command/return module doubles as a reservoir).
So materials lab with a dock port on top, Lander Mk 1 can in the middle, smallest rockomax fuel canister with a Poodle engine and 4 basic landing legs on the bottom. Also, though less important for its operation, 2 mystery goo canisters, thermometer and barometer for science. Two (coloured) lights pointing downwards for better determination of how close to the ground I am. An antenna and RCS controls would have been a good addition, but I forgot about them until it was too late.
The command module was just a basic Command mk 1 with the second biggest Jeb's fuel canister with a Terrier engine, plus usual commodities (batteries, RCS and tanks, heat shield (you don't really need much of it), two radial parachutes, docking port, etc). I... forgot about the antennas there too. That's about three or four times the delta-v you need to get back to Kerbin, even from ultra-low Minmus orbit, so you have a lot of spare fuel for the lander.
I also had an extra stage with the Mobile Processing Lab that got all the way which I didn't end up using because I don't understand how it works yet. Next mission, I guess. Putting the whole massive thing into orbit would have been way easier without that stage, though I have to say I have much to learn about how to build efficient launchers.
The main problem with this setup is that there is space only for one person to go back to Kerbin. You can do the mission with a single Kerbal (assuming you don't forget to put RCS thrusters in the lander), but the reason you want to send a Scientist with the lander is that they can reset the experiments in between hops (materials lab being the most important). I did the whole crew report, eva report, surface sample, materials lab, mystery goo, temperature, pressure science thing in 4 biomes. You can do 2 small hops with this lander and still have enough delta v to get into orbit, but I messed up my second descent into Minmus (busted one of the lander legs; could still land, but without SAS it was way too annoying to bother; and landed on "Minmus Midlands" more than once, so I couldn't take science from there again).
Considering the extremely low gravity in Minmus, you could also land a whole rocket on it and do hops with it, but I don't trust the basic landing legs enough for that. Oh, I did increase the spring and damper strength of the legs before the mission. Not sure how much of a difference it ended up making.