Just found on the internet via various searches... call to verify that they still allow pets! (called Super 8 Motel in Prince Frederick, to double-check because I heard it allowed pets!)
DAYS INN
21847 THREE NOTCH ROAD
Lexington Park, MD
301-863-6666
Super 8 Motel
40 Commerce Ln.
Prince Frederick, MD, 20678
410-535-8668 (NO EXTRA PET FEE!)
Best Western La Plata Inn
6900 Crain Hwy, Rt 301
La Plata, MD 20646
301-934-4900
877-356-4900
Days Inn of Waldorf
11370 Days Court
Waldorf, MD 20603
301-932-9200
Howard Johnson Express
3125 S Crain Hwy
Waldorf, MD 20603
301-932-5090
800-826-4504