When I was there last weekend, I had a water pressure drop in the house. When I winterized before I left, I drained the tank but only got a couple of gallons of water.

I have never had to mess with a pressure tank.

It is my belief that a small hole has appeared in the bladder which has let the water leak and rise to the top of the tank above the bladder.

BTW, I didn't think about checking the points on the switch.

Does this stuff make sense?

I think it does. A couple of things that I have personally experienced with a bladder tank....loss of air pressure. We had one that would leak air, and it caused the pump to cycle on and off constantly. I was always adding air to it. This was easy to diagnose as the water pressure at a faucet would vary as the pump cycled, and it was happening too quickly.

Foreign debris in the water side of the bladder tank. Our well pulled up a bunch of sand once, which accumulated in the tank and restricted the volume available for water. This was diagnosed easily also, as the tank weighed about as much as a fluid-filled rear tire on a Ford 4000 tractor.

You should have a pressure gauge n the system to verify set pressure of the switch.

As for the tank being waterlogged, typically, there is a Schrader valve on the top that is used to measure and adjust pressure. If memory serves, you drain the system to relieve pressure first. You want the pressure of this to be 2 psi below cut in pressure of the system. In other words if you run a 30/50 setup set the pressure at 28 psi.

The one time I had the bladder fail in a pressure tank I had two symptons:
1) pressure drop slightly
2) pump kicked on and off repeatedly, I suppose to raise the pressure.