Tarheel1999

The fuel flow arrows are  not reliable. You are better off ignoring them. Fuel at the same priority level drains evenly. Changing the priority level or adding fuel lines will change how tanks drain. 

Can't you just hover over the root part and press "h" to split the rover from the pylon?  Many moons ago, a new functionality was added to KIS to separate multiple connected child parts from the parent. If it's not "h" it's another key. You can look at the settings file in the KIS directory to see what the hot keys are.  I would suggest building a simple test craft at KSC (maybe a command pod with a bunch of girders attached in different fashions) and fiddling around to find out exactly how it works.

Understood. You can't "dock" things in the Editor. The "decouple" option is what you get when you stack something on a docking part in the Editor. When you hit decouple in space the parts separate and slowly drift apart. Have you tried time warping to speed up the drift? This works fine in my modded install and so it is probably an issue with your ship design or your install.
The camera/exploding parts issue is probably due to precision errors. If the decoupled vessels are literally on top of each other, bad things  will happen when you reload the scene.