I'm not sure there is a limitation as far as Wyndham is concerned. I know 14 nights per reservation, but you can make back to back transactions (probably have to change rooms) of 14 days.
Some states may have laws regarding this, although i'm not entirely sure Wyndham's reservation system would be able to recognize this, and above and beyond that, i'm not sure it's something they would try to enforce if you had reservations.
I know Florida has laws about this, and some Campgrounds and "extended stay" hotels actually do enforce this. In Florida it's 14 nights. Again, I don't know that this is enforced. I know people who have stayed at BC for 30+ days before. Also all you have to do to get around this is to stay somewhere else for one night. Changing after 14 nights may suffice for this requirement.