HAVE A GRAND PIANO? This large and comfortable young Colonial has light-filled, airy rooms with a relaxed floor plan perfect for entertaining family and friends.  Located in Littleton's rural northeast corner on the Westford line, this house abuts Beaver Brook Estates neighborhood yet is minutes to 495, 2 and the Commuter Rail.  Thoughtful features and amenities include the priority bells and whistles: granite countertops, hardwood floors, JOTUL wood stove, separate laundry, master suite with glamorous jetted bath, pull down attic stairs and superb closets.   The bright walk-out finished basement has an in-law's dream set-up with pretty kitchenette, studio, built-ins and a fancy bath.  If you love to garden and be outdoors the well-landscaped acre with a row of fruit trees offers lots for you to enjoy as well.  Well-priced, this is a Fabulous Opportunity.