From Portland area:

Take the Maine Turnpike North to Exit #63 in Gray.  Follow Route 26 North to Main Street of Bethel, Maine.  You will go through the towns of Poland, Oxford, South Paris, West Paris, Bryant Pond and Locke Mills.  As you approach lower Main Street you will cross the railroad tracks.  Proceed straight ahead. There will be a Key Bank on your right.  Take a left directly across from the bank onto Chapman Street.  Follow this street and just after a sharp curve to the right, you will see the sign for Crescent Park School on your left.

From Rumford area:

Follow RT 2 West to Bethel.  After passing The BIG Adventure Center, you will cross the Androscoggin River and continue on Bridge Street.  You will come to Rite Aid on your right and a blinking red light.  Take that left onto Parkway and continue to the end.  Take a right at the end of Parkway and continue straight.  You will cross the railroad tracks and continue up Main Street.  You will come to a Key Bank on your right, Chapman Street is on the left.  Take Chapman St. and follow this street until you reach Crescent Lane on your left. 

From Gorham, NH

Follow RT 2 East into Bethel Village.  Turn right onto Church Street following the street past Gould Academy.  Continue through the intersection of Main St. and take your first left, which is Mason Street.  Follow Mason St. until you see Crescent Lane on your right.

You can also use MapQuest to get directions.