@Christine3142 Yes, you should definitely mention everything in your ad that could be a potential deal breaker or lead to a bad review. For some hosts it might be traffic noise, or barking dogs, or loud neighbors, - you want to ward off guests who will be prone to complaining.
Just talk about it the same way you did here- that it's in the historic downtown area, with all those great things to do within walking distance, but that the flip side is that there happen to be 5 homes on your block which are rundown, vacant and a definite eyesore. You might want to reassure guests that they don't present any safety issue, i.e. they aren't hang-outs for squatting crackheads or anything (assuming that is true).