With a 12 Volt blower motor, no resistor is needed. With the 12 Volt switch you are set to go. The cable to turn the water on and off to he core? I would find an aftermarket cable that is long enough and a mount that attaches to the under side of the dash. My truck has some holes down there that would work. If you can find a cable with an H on it that would be nice. You will have to make some sort of clamp at the firewall to attach the end of the cable and direct it to the valve, but that is not too hard to do. I have the same setup in my truck, 52 1/2 ton but the cab is the same. I just turn that valve by hand according to season. If you can find a heater cable that is long enough it might have the "wrapped" end that fits over the pin on that valve. I have not seen the bits that make up the control cable on any Vendors site, so if you do let me know.

Steve H