I would suggest trying to find the following book in a library near you or through inter library loan (purchase would be expensive, I think):
Maine cemetery inscriptions. York County
Author: Maine Old Cemetery Association.
Publisher: Camden, Me. : Picton Press, ©1995.
Series: Maine Old Cemetery Association special publication, no. 1
This book series is a really great resource; it helped me find a tiny little burial ground off Rte. 112 in Buxton in the back corner of a private farm.
The area of Maine you are searching in for burials in that time frame could make your search more difficult. From experience I have learned that many burials took place on small family plots and in some cases private land, and have become overgrown with trees and in some cases the little cemeteries are almost completely hidden by forest. Not to say it's impossible to find a grave there, but the locals might be the best way to go...
You could try writing to or calling:
Buxton - Hollis Historical Society
Box 34, Buxton, ME 04093
They are probably open more often in summer than other months; and weekends more so than weekdays.
There is also a Limington Historical Society:http://www.limingtonhistory.org/
If your ancestor was a Rev. War pensioner, there may be further information on him withing their holdings at Limington His. Soc.