It's hard to quantify the risk from the information although here in Australia, by the time something is described as transitioning, it's usually ok. I think getting hard statistics as well as spending time in the neighborhood is important. Also every neighborhood has better and worse parts. For example I am considering buying an IP in a very rough neighborhood because of the bad reputation houses on one side of the street are $100K lower than on the other side (a very popular family orientated neighborhood) [Both houses are in the same school zone, so it's not that, it's seriously just snobbery]. It's only a matter of time before people realise the madness!
I have lived in a transitioning area, and it was generally ok. The main problem was MMM advocates walking and biking, but you do less of that and more driving to stay safe. But once your are in your (secure) house, it's no big deal. I'd do it again if the savings were significant (as they were at the time - rents in the area have since caught up). I don't weigh much more than you and am also female if this helps. I also spent very little time in my 'hood, choosing to drive to a nearby area for shopping, the park, excersising etc so you may want to factor this time/money cost in. For a small saving it's not worth the hassle and lack of pride (not from snobbery, but just having to be surrounded by ugliness and chao - unlike the area where I want to buy the IP, this area was not very pretty unlike the nearby richer area. The IP area is pretty with nice streetscapes.) But if the numbers are significant, why not. At the end of the day it's who is/what is inside your home that matters :)