Well, it's not wrong, but not the best way.  The OSM nominatim service will put your desired end location at funny spots if it's not sure where the entrance is - I had issues with it when asking it to get to airports.

How exactly are you specifying the end location.  I noticed you tagged this house and I would have thought it would make things worse, by default it would have used tiger data which marks numbers along the road .

Perhaps actually marking exeter as an alley would help, marking it as unpaved is one thing that should be done regardless.  Giving driveways to houses probably would help too but I'm not too sure on that.