Andy, that's NO Prozac moment!
You're most ambitious, yet most of what you desire here is presently available in reality.
I saw in the other thread where you found the "Berkshire" company site for lights. Solved.
You want running autos? Go to the next trainshow early and breeze through everything looking for Aurora Thunderjet HO equipment and supplement with new gear from the two sites I've mentioned. Voila, moving HO cars. Don't want slot track? Get the Faller system. Solved!
Moving people? Glue a bunch to a moving belt with the ends hidden by buildings or a truck. Solved!
Working gates? NJ International. Solved!
Moving skiiers? NOCH has them. Solved!
Real water? Listen to your friend in the hobby shoppe! Solved! (fuggedaboudit!)
Moving animals? Glue a bunch of cows to a conveyor belt like the one for people. Want a spectacle? Have them going from out of a truck and into the back door of a McDonald's! Solved!
Automated switching? CMRI! Solved!
Automated layout? Again, CMRI. Solved!
Now here's the one you have to solve for me. Want an automated layout w/CMRI? Fine. I understand that you want to sit back or leisurely walk about while taking everything in. What will you do when you hear the tell-tale rattle of a derailed wheel, the train is approaching a bridge and the nearest throttle is clear around the layout?
It took me years to get further away from the controls than six feet. My last layout operated flawlessly to the point that I could turn out the lights in the room, turn on the building and street lights, leave the layout room and look at the trains through the window from OUTSIDE. That was fun. In 8 years, I had maybe two catastrophic derailments while playing tourist outside.
I taught my wife how to recognize the sound of an impending derailment, and to hustle and kill the main power switch to EVERYTHING if she was closer to the cockpit than I.
I didn't need a computer to do that.
Happy Rails!
George.