My 2007 Ram also wanders a bit requiring constant slight correction when on the highway. Done this since new. At the time others on forums had stated similar experiences. I had the Dodge dealer replace the steering linkage with the newer design found on 2008+ rams. Much heavier tie rods etc. Didn't help.
Others on forums have stated that Dodge's typical alignment settings have too much camber causing the wander. I don't know much about that sort of thing and have yet to have a shop adjust it different than Dodge specs. Anyone confirm this issue?