In case anyone's interested, I've taken a few shots of the propane installation. They can be found here..
I originally had it installed in the tool box in the bed, and had used the standard 1/4" boost line, and vapor line to the intake that came with the system. One of my problems with the system was the length of these lines. With the control module in the tool box, the lines needed to be several feet long, which I suspected was delaying throttle response. By moving the control module to under the hood, the length of the hoses could be reduced drastically. Now, the line from the MAP sensor to the control module is only about 36" long, and the supply line to the intake is only about 18" long. To further increase flow, I ran a 3/8" line from the tank under the truck to the control module, and also used 3/8" line from the control module to the intake. The system originally came with a TYMAR elbow that had a 1/4" hose barb brazed on. Since I changed to 3/8" line, I drilled and tapped a fitting for a 3/8" hose barb in the metal section between the silicone boots on the intake, and went back to the original TYMAR elbow.
The result: a whole lot more output of the system, and much quicker response.