Finally!
I managed to do a semi-precision landing with my 2nd lander. It wound up 27.8km from the first lander and I was also able to use the tiny bit of fuel left in the transfer stage to re-orbit it to serve as a mapping and communications satellite.
I did mess up a tad on landing, I selected the other ship as a target just to watch the distance on it and what happened is that my navball switched from showing my velocity relative to the ground to the velocity relative to the other lander on it's own. So I burnt a lot of fuel trying to 'slow down' and my velocity wasn't changing until I realized the navball screwiness. By the time I put down, I had burned off about a fifth of my fuel.
I decided to go ahead and re-orbit it just to verify the entire life-cycle of the design from initial launch, to Laythe insertion, to descent and finally back up to orbit to deliver Kerbal scientists to the deep space cycler.
I had to re-load a couple launches because it was hard to figure out the precise altitude to do my gravity turn. I wound up turning around 7km (after keeping my throttle as low as possible before that point) and burning hard. When I got my apoapsis above the atmosphere, I used my RCS thrusters to continue accelerating me while I cut the engine and cruised to apoapsis. Then I had to gentle nurse the throttle and did four or five burns where I'd raise my ap, then cruise to it, raise it again, cruise to it, etc. That was the absolute most efficient way I could do it and I still wound up with an orbit with just seconds left of fuel.
There are a couple of new bugs I found in this lander that I'll have to fix:
The side tanks are too tall and make the CoM too high which leads to instability issues. It's particularly hard to land on a tilt because of the high CoM. I'll have to swap those tanks on the side for low, wide ones.
I'll have to rework the ladder system as placing the legs lower to protect the engine bell means my ladder doesn't quite reach the ground. It gets nearly there and I'm sure a Kerbal could still reach for it but I would rather be safe than sorry.
I need to strut the side tanks to each other, not just the central core. On one landing attempt at 12m/s, they wobbled and broke off.
I'm probably going to add more fuel and switch to the mainsail for increased factor of safety. I know I would have wound up with more fuel without the errors I made, but it's still too close to comfort.
Oh and the docking port I put on the cruise stage is useless; the decoupler seperates the cruise stage from the lander but doesn't detach itself from the cruise stage so the cruise stage is floating around with a decoupler and engine fairing blocking the docking port. I'll have to put the docking port on the bottom of the next launch.
If the update doesn't wipe out my save, I'm going to redesign the entire lander and launcher from scratch (using math) for absolute optimal efficiency. I was happy with how well the launcher worked but I suspect it could be made even better. The lander was also acceptable and once I send out orbital tugs to deorbit it and capture it and dock it to the station, I will feel comfortable using them with Kerbals. But I'd still like to see some deltaV improvements. I *may* investigate attaching a couple of NERVAs for use out of the atmosphere but that extra weight is going to suck hauling around.