There are dog services, and then there are dog services. Maureen is the latter. Dependable, caring, and honest she has been walking our dog since the late summer. Be warned, we pay slightly more because we're outside of the "normal" Tremont area (in the flats), but for us it's well worth it. She'll text with updates on your dog and watches for anything unusual / unfavorable that may come up.
I'd recommend Maureen to anyone in the area. That said, if you can swing it I'd couple her services with some kind of day care once a week where your dog has more full day play time interaction with other dogs - i.e., the Mutt Hutt.