I got hurt pretty badly on PAT. I can tell you that the only accurate source for questions is the paper DAT registration packet. Too bad it has only a few questions per question type - it's hardly enough to practice.
Given that terrible climate in PAT prep materials, I would just practice until I got a 28 or higher on Kaplan or Top Score Pro practice tests. Even still, I think that the real PAT questions are structured differently from those on Kaplan and Top Score Pro tests so I can't say even that strategy will work well.
A few people have mentioned Barron's as a better source for PAT questions, I can't really say anything on that as I didn't use Barron's for DAT prep. Perhaps people here can elaborate on their Barron's practice test scores vis a vis actual PAT test scores. It would be even better if someone could comment on the similarity between Barron's PAT questions and those they encountered on the actual PAT and/or the DAT registration booklet. I realize that this latter information will be subjective, but it is very important to know. Perhaps you can do the comparison yourself, start with Barron's, switch to Kaplan, and then maybe Barron's again and then do the official DAT registration booklet. This will let you compare and contrast. If Barron's is close to the DAT registration booklet, then you have found a good resource for PAT practice.