I did plenty of electronics this year on my team and I have a few pointers that I could give:
A. Don't lose anything.
This year I managed to misplace both the PDP and the roboRio. Make sure you have shelves where you can store everything and you keep your workspace neat and organized.
B. Try to keep the electronics as far away from any parts that can move.
The last thing you want to hear is that your encoder stopped working because the wire was dangling out of the bot. I suggest using zip ties, zip tie holders (
http://www.amazon.com/Startech-HC102.../dp/B00008VFBE ), and a lexan board with 1/4 in. holes cut into it so u can put a wire against the lexan plate and put a zip tie through the holes and around the wire to keep it secure and keep your electronics in one place.
C. Get an electronics tool box
Having all your necessary tools as well as things you know could break in one toolbox definately saves you time in the pit and build season from not knowing where you placed something. Just keep it with you at all times.
D. Check all your connections pre-match
After every match your bot's wire connections may have been loosened. You should stay in the pit and check all your connections before the next match and run a systems check to see if everything is still working. You could also check the mechanical connections such as checking for loose bolts (shouldn't be an issue if you used lock nuts but your never know).
As for CADing the electronics, it is definately possible as there are pre-CADed parts that you can download with a bit of searching. I definately recommend CADing the electronics before attempting to randomly put them on because the other engineers need to know before hand if you will need an extra electronics board machined out.