Thanks guys. Don, thanks for that offer. I'll take you up on it when the time comes. But I think my discovery tonight gives me time to re-evaluate the need to open it up.
My plans for tonight changed, so I had time to work on the 782. It was an evening of "Good News - Bad News."
Good News: It turns out that my PB Blaster treatment on the footrest bolts was effective. I was able to get a vise grip on the heads and a socket on the nuts below - slowly all six came off.
More Good News: Once I got the hydro area cleaned up some, I started the tractor and raised the snow thrower, and immediately saw the Hy-Tran flying. You can see it at the 10 second and 30 second points in the video:
http://youtu.be/btsc93OZZKw
Bad News: My tractor apparently came with the rare two part flare on the lines, which allowed the line to "chatter" under pressure.
Good News: I think I solved the "chatter" sound mystery.
Bad News: I couldn't get the line reconnected to the hydro(to minimize leaking until replaced), so I decided to disconnect the other end of the line from the hydraulic lift control.
More Bad News: There's not much room under the dash to loosen the nut.
Good News: Removing the gas tank will give more room to work.
Bad News: I discovered the shut-off valve on the gas tank is defective - discovered AFTER I thought it was off and I removed the fuel line.
Good News: Gravity flow works well without a fuel pump.
Bad News: Gas tank was full and gas quickly soaked my shoe, pants, floor, rag, etc.
Good News: I finally got the tank emptied into my F150 tank.
All in all, I'm happy with the good news. I got the footrest bolts out & like Steve B said, it would have to be done sooner or later anyway. I found the leak and I'm optimistic that is where my leak was all along, and I may not need new hydro seals.
I really appreciate all the input from everyone, and I'll let you know if my problem is solved, or just reduced!