The standard lance from the waxoyl people is not long enough to reach all the way down the sills. The rear part of the sill is accessed from the front of the rear wheel tub.
make sure you keep the wax good and warm, thin it with white spirit about 30 to 50% to spay box sections.
Cover the floor with a sheet of plastic, as it comes out of the drain points and gets every where.
take the door light switches out to get in to the A pillers, B pillars through the drain hole at the bottom, take kick panels off to get in to the box section at the bottom of the front panel.
Plugs for dog legs are near the front bumper step mounting bolts, if you have the original sill plugs use a screw to get the center out they are two part plugs, screw in to the center of the plug and pull out with pliers.
I would also do the inside of the doors, tail gate, and engine lid while your at it.
Well worth doing, just dont smoke, and I would have a bucket of hot soapy water and a sponge at hand to clean your hands and any runs.