PS fluid goes the other way - out of the box, through the cooler, to the reservoir. You can catch it out of the box or before the reservoir.

Good question about the mount. It might degrade a rubber mount but I don't know about a sealed fluid filled mount. Check the gap when you go under the car. I can't think of any preventive measures after PS fluid rains on it other than a brake parts cleaner rinse.

Sixto
87 300D