12.92 is a great resting voltage considering the parasitic drain from the gizmos. Hopefully you're not reading that with the Shore Power or solar connected though, right?Glad you chimed in, Bill. I just used the multimeter to check the battery. It read 12.92 volts, so I think it's good. That's usually what it reads (or lower) in the mornings when we're using the solar kit. So it seems like my removing the cut off fuse is where things went wrong. Given that none of the lights work (the easiest to check whether my battery is working is the orange exterior light just above the tongue), it seems like no power is getting beyond the cut off fuse, which is right at the battery. I'm left to wonder whether debris got into the housing when I pulled it out (unlikely) or WTH is going on. I'm such a novice with electricity, sigh.
Like @Firehawk068 said, start looking for blown fuses and/or fried wires. You can also look for shorts to ground by unhooking your battery, unplugging Shore Power, put your red probe on the hot wire and black on a ground. You're checking for continuity here so set your meter thusly and listen for the tone. If you have tone you'll need to find where/which wire is still shorted. Do that by determining which direction it goes in (ohms) and chase it down. You don't have very long runs there so it shouldn't be too hard.