Just finished installing a Reese signature series 18K sliding hitch in my '03. Took a long time, about 6 hours. Had to drill 4 holes in the frame 21/32", 4 holes in the bed 2-1/2". I have the specs from Dodge on drilling the frame and it is within the guidelines. Worst part was fishing the bolts through the inside of the frame about 20" from the entry hole to the hole they come out, the bolts are special with splines so they bite in and lock in place as the you tighten them. Had to buy a couple tools for the job I did not have, a torque wrench that went to at least 170lbs of torque, a 1/2" drill, the 21/32 bit has a 1/2 shank, and a 1-1/2" open end wrench for the special bolts for the floor mounts. I am picking up my new trailer tomorrow so I will report back on how it works. Here are a couple pictures from the install.
This is the frame laid out as it sits on top of the frame rails.
This is the frame laid out as it sits on top of the frame rails.