Don, My son essentially did what you are wanting to do, with my Challenger75.

I gave him my credit card and sent him to a truck salvage lot. He came away with tanks, hoses, tractor protection valve, Johnson bar, pressure gauge, glad hands, and a stop light switch for less than $100.

Talk to the guy at the salvage yard and I'd bet he'll get you all fixed up. I didn't put a foot pedal on the tractor but it wouldn't be a big deal. All the Johnson bar and food pedal are, is a pressure regulator that feeds the service line.