I would not be able to share any documentation with you but it would depend on what the disaster was and what service was affected.
We have two long distance carriers, redundant sites, redundant DS1 Boards and Signaling Channels, ability to re-route Toll Free numbers to different DNIS or POTS lines instantly, Bank of Centrex lines with 3rd long distance carrier. Ability to change our main long distance carrier to backup long distance carrier on our inbound toll free with SMS routing. 2 phones on the desktop, two IPSI boards per site, trunks coming in over both fiber and copper lines from the same network vendor, I could go on and on. Sounds like you are doing the normal maintenance stuff.
If something were to fail, I would juggle one of my solutions, in many cases I have more than one solution to fix a problem. You could document your sytem if "X" happens then do "X". A good way to start is by creating a network diagram listing all of your services, adjuncts and systems including network vendors with contact info, circuit ID's, account numbers, DID Ranges.