1) Great drive-in takeout place with picnic tables, etc., very kid friendly:
George's Surf & Turf - 116 Uxbridge Rd (Rt 16), Mendon, MA
(about 2 miles away)
2) Nice large family restaurant, something for the whole family
Lowell's Restaurant - 75 Cape Rd, Mendon, MA
(about 5 miles away)
Hope this helps....