Maplewood, Missouri, came in at No. 1.dan donovan/Courtesy of The City of Maplewood Beautiful homes on a tree lined street in Maplewood, Missouri.Maplewood, Missouri, is GoBankingRates’ best small town to retire in the U.S.The community, a suburb of St. Louis, has a livability score of 87 out of 100 and estimated monthly expenses of $2,810.Two towns in Pennsylvania round out the top three—Sharpsburg in second and Brentwood in third.Approaching r…