Your observation about the most troublesome switch being the one hardest to reach is so true! 
And so annoying. I use DZ-2500s wired for TMCC CAB-1 control (DZ-2001 Data Wire Driver) and push-button operation on the fascia (where applicable). Some advice that might be generalized to other brands:
- Test the switch on the bench BEFORE installing on the layout.
- Program the switch (if it requires that) on the bench BEFORE installing on the layout.
- Plan for access to the switch - a pop-up hole or hatch. "Stuff" is going to happen. It's not a matter of "if".
- Consider a physical or manual way to throw the switch. I think there's a company called Bluepoint that makes a flexible mechanism for mechanically activating switches. They are part of my Plan B.
I have 42 switches on Panhandle 2 and all but one are powered. The other is a dummy that will be fixed in place. Reliability is extremely important to me, so this is a topic I have given much thought to. I'm only beginning to install switches and track, so I'm keeping notes on what happens.
Best of luck,
George
