The MSAR won't give you a percentage accepted, but if you check out percentage interviewed it'll give a picture of how seriously out of state applications are considered. You want a school that interviews at least 10% of the out of state applicants, but the best bet is to crosscheck the % interviewed IS vs. % interviewed OOS, and look for values that are somewhat close (st. like 25 vs. 10% would be good, as opposed to 30 vs. 4%) Also, consider state schools near your home state, as they'll give you some extra consideration as having an interest in the area (i.e. being more likely to matriculate there and hang around after graduation). Language on the school website is also helpful, and you're looking for something like "qualified out of state applicants are encouraged to apply" vs. "only a limmited number of spaces exist for out of state applicants". Strict MCAT/GPA cutoffs are also an indication that the OOS road is very tough.
In the end though, besides the numbers game, if you're looking to beat the odds and go out of state you want to show some kind of vested interest in the area. Family, Undergraduate School, etc. will definitely help you make your case.