You need a helper or a remote starter. You can cross the field and batt posts at the solenoid to operate the starter. This can be done with a screwdriver, but it is much safer with a remote starter wire tool. You can make this tool with some wire, 6 to 8 feet should be plenty, and two alligator clips. Your starter solenoid should look like
THIS ONE >CLICK< Cut the wire to two equal lengths and install an alligator clip on each one, click one wire to the batt. feed post, and the other to the "signal from ign. switch" post. Now turn the key to the run position, and make sure the truck is in park or neutral with the brake set. When you touch the two wires together the starter will engage, there might be sparks and that could alarm you at first, but don't panic. Now you can get where you can look for the spark of ignition and operate the starter from under the hood.