Sharpy

That's not heading in a good direction...
1. With a good reaction wheel (and a plenty of electricity to keep it running) you don't need RCS. RCS is useful when going up really steep slopes, or especially if you jumped off a ledge too high, to brake your descent. It's not essential though; you shouldn't use it for roll at all (switch actuation toggles for yaw pitch roll off), and then you won't need much monoprop. (with RCS rotation control, no amount of monoprop will suffice).
2. Sooo big, flat, it will be hard to keep stable. On Mun, when driving, you spend 80% of time "airborne", and use the reaction wheel more than steering. You absolutely don't need that many times the science experiments if you have a scientist and the box.
My suggestion: make it way more narrow, look into the "aerodynamics" tab for some wing parts that make much better frame elements than the heavy girders (if you flip and crash, you won't benefit much from the frame surviving if the rest goes bang.) Make steering/acceleration different than yaw/pitch/roll controls (WSADQE), e.g. arrow keys, and when driving, SAS to prograde (Surface mode, not Orbit!), right hand on arrows, left hand on Q/E to fix roll to stay wheels down (SAS will take care of pitch/yaw), turn by gently tapping simultaneously left+a, right+d.
And really, really if you can scrunch that bit of science, get the ruggedized wheels. Unless you plan to take a three-star engineer to fix this crap. You won't visit all the biomes with these.
 
BTW, all the clever "skycranes" that try to land your rover wheels down, engines overhanging to the sides, undock, then fly away towards the setting Kerbin? Overkill like heck. Good reaction wheel, one decoupler stuck right to the "butt" of your rover, one size 1 medium fuel tank and a Terrier engine. And maybe a fairing. That's all you need for your "skycrane". Set down on the Terrier gently (or not so gently; if it blows up, no biggie), then use the reaction wheel to tip over onto your wheels, then decouple the tank and the engine. And if you didn't tip onto the wheels, just roll onto them using the reaction wheel. You SHOULD have enough torque to do that. If you don't then your rover wouldn't survive long anyway.

Planets in KSP don't orbit in exactly the same plane - their orbits are inclined more or less relative to Kerbin orbit.
That means you may need to add normal component to your ejection burn to make the encounter, otherwise you'll fly "below" or "above" the target planet's SOI.
If you perform the transfer in such a way that your encounter happens to be at ascending/descending node, then no plane change is needed. But if it happens right between the two, you'll need a large normal/antinormal burn - and this value is the most pessimistic value for that burn when trying to encounter given planet, when you start your burn from equatorial orbit.
Note how no values are given for Mun and Kerbol. Mun being in equatorial orbit, and Kerbol being Kerbin's central body, so any departure inclination works.
(and these figures have very little in common with inclination changes *at* the destination. When departing Kerbin for Moho, the change between arrival into equatorial or polar orbit is of order of 0.1m/s. But to reach Moho SOI you may need to spend 2520m/s on a normal burn, on top of 950+760=1710 just to drop your periapsis to reach Moho orbit.

PreciseManeuver is a PreciseNode fork that doesn't have PreciseNode's weird interface quirks (just its own, new ones )

First, unless you're already rather good, and you fly a nice plane, yep, forget the runway, land on the grass. And have the rear brakes stronger than front brakes.
Then - before even attempting landing - learn to feel your plane and maintain descent velocity and forward velocity.
Start. Throttle down. Just a notch or two above the bottom is usually the right power. Maybe a bit more if your plane has poor lift and is draggy, but for "graceful" planes, one notch above bottom is exactly the right power.
Then try to get your pitch such that numbers on your altimeter change by no more than 1 per second. Maintain that, wait until your horizontal speed stabilizes. It will be different with different planes, ones with great lift and superb aerodynamics will stabilize at 40m/s or less. Lean rocket-like heavy SSTOs may stabilize at 200m/s and require way more throttle not to drop. All are fine. Lower is better, but you CAN land your plane at 250m/s. It's just harder.
You'll notice your plane has rising or dropping tendency - left alone it will either start dropping faster, or stop dropping and start rising. No problem here, just learn which way it goes.
By the time, you should be waaay out to the sea.
Turn towards KSC. Aim somewhere off so that you don't crash into anything. Get your altitude to 100m, changing it very gently.
Try to learn how to guide your plane so that you cross the 70m level going downwards very slowly. Try this a few times. Pitching very gently up or down, manipulating your vertical velocity and altitude.
Finally, Land Ho! Get to some 80m and let your airplane start dropping, very, very gently. Don't touch anything.
If you have airbrakes, activate brakes just before touchdown, If you have just wheels, you can activate them way early out over the sea.
As your wheels touch the surface, shut down the engines.
Then keep not touching anything. Trying to correct is more likely to get you crashed than whatever "bad" happens due to not trying to correct.
 
Really, simple steps:
- level your flight and stabilize speed waaay early. Since then only very gentle corrections.
- maintain altitude around 80m until you're really close to the land.
- start losing that, very gently.
- brakes on, engine off.
- don't touch anything.

Eh. Found it. ModuleManager 2.7.5 - the newest one. I was fairly sure I did have the newest, but nope.
Now everything works.

Edit the save to drain all the fuel? Or edit it to set thrust limiter on all engines to zero.

Scratch that. Autostrut kicked in. Spiders still work, but not for wheels.

All Connector pieces (conversions between various sizes) have around 8:1 wet:dry mass ratio. This tank does too. It has worse dry mass than a dedicated tank not because it's MK2 which have wing area, but because it's a connector, with two different sizes on two ends. And with its shape it would have very poor lift properties...

Okay, I'll answer my question myself, as I got impatient and did some experimenting. I built a "floor" of wings, with a tower in the middle, with tanks and engines attached, facing the "floor" and fine-tuned the engine height for when the thing would take off, or refuse.
About all engines I tested (from Swivel to Mammoth - only Twin Boar defied the rule, for obvious reasons) act at a distance of about 4.5 lengths of the Modular Girder Segment XL  with very little variance - only Twin Boar required 7 segments from attachment node height, all the rest fit well within 5 from the engine attachment node (and most - except Mammoth - within the lower half of the 5) to the object they interact with. Interestingly, that's completely regardless of the flame animation - some will refuse to fly with the "floor" still far from the flame, while the larger ones burn clear across and fly just fine, moved a notch one way or another.
 

This tutorial is for building radial separators out of the structural pylons. It's a bit convoluted process but it works "as designed", leaving the two crafts separated cleanly without any stubs, and the discarded separator floating freely.