(Edited 8/27.... Problem now diagnosed. My mechanic has now found out that the vacuum pump is toast)

I was on a 12 hour drive and all went well until 8 hours into it. I took an exit off the highway and when I coasted to slow the car from 70 mph down to about 40 while coasting, it sounded like there was a small "poof!" sound like something blew, and the engine sounded a bit rougher but I turned the radio down and tried to listen but I thought maybe it was just my imagination.

Then.....

1) When I applied the brakes to stop, I no longer had power assist brakes.
2) When I accelerated it either was getting no turbo boost or maybe more accurately no kick down. The car would accelerate but didn't have any real get up and go.
3) When I stopped the car, the engine continued running. I had to use the "STOP" button on the engine to stop it.
4) When I restarted the car and drove it, there were some hard shifts.
5) When I went to lock the car doors with the key, one did not lock.

Sounds like a vac problem somehow/somewhere. I didn't do anything that would have moved any vac lines and this problem would almost have to be a tee intersection to cause this many problems all at once. I had a smoke test done about 3 years ago and they changed out any questionable lines or tees at that time though. Maybe the vacuum pump quit? There was a 12 inch spot of clear liquid under the car one day, no odor to it, that I figured was just a/c condensation but maybe it leaked out from the vac pump but I'm not sure if they have any fluid in them or not.

Any suggestions on what might be causing this?

1991 300d, 223k