Opinions on used Ford Escape

We have been using my MIL's 2015 Escape Titanium for the last couple of weeks and it seems to be a fine little SUV. We had it serviced and inspected and they didn't find anything wrong. All recalls are up to date. We are thinking of buying it from her because she is elderly and doesn't drive it much as in only has 58k miles. I guess I'm going to have to look up problems associated with the RDU? I don't even know what that is.