Larry and all,
The removal of the panel was a pain in the butt. The connections on the backside are many and in my case the panel did not have enough plumbing slack in the pipes to allow it to tip out enough to have reasonable access. The worst cause of this, in my case, was that the valve manifolds that were attached with metal strapping and screws and nuts that did not have any reasonable access.
If the manifolds could be released from the frontside that would have made all the difference in the world regarding this job. My recommendation would be to build some manifold mounts that can be released with sheet metal screws from the frontside and install those the first time you remove the panel. Photos of my mounts are attached. The manifolds are wire tied to the mounts.
I also marked everything back in the jungle of wires and pipes, with a sharpie, that needed to be disconnected to pull the panel. That makes it clear when you are peeking behind the panel with one eye or a mirror what needs to be disconnected. If I was at home when I had to remove the panel I would have modified it and had it cut just below the bottom manifold valve, horizontally, so that a smaller panel could come off to gain some access to the sensors and sewer valves without pulling the full Monty.
The message is, if you get in there, spend a little time to make your life easier next time around. Hope this helps.
Later Ed