I had it aligned a couple months ago by a reputable service center. I had knocked it out on my way home from hunting one evening (long story) however the wandering issue has been around a long time. They told me that I could bring them a kit for the caster adjustment and they would put it on and align it for 140.
My general mechanic will install the gear for 100 but I'm not sure which gear to buy.
Right now I'm leaning to put the caster at 4.5 degrees and then if that doesn't take care of it put on a new gear.