Thanks for posting this, David.
Cover is on and the tripping problem should now be at least reduced since I was able to split the circuit such that the kitchen and den are on one breaker (now #7) and the hallways on another (#8). In addition, the LC extension cord (to which the overhead light strings are attached) has been removed from that same circuit and put on #6, which is powering a temporary receptacle in LC that we're also using for our power tools.
All nine of the other breakers are turned off since they're no longer doing anything, although I'm unwiring them only after confirming what they're actually attached to. Most of these were to now-defunct lighting and power circuits in the bar area. Next week several will be repurposed for new receptacle circuits in LC to be installed along the newly-sheetrocked walls.
The note taped to the front of the panel now reflects this new condition.
Some of these circuits are going to be hard to trace and if so will be left in place for the time being with the breaker off, so if anyone notices a loss of power to anything that was working as of last week, please let me know.
If possible, I'll get the den onto a separate circuit from the kitchen.