Neldon - Nulton in PA 1770-90
It appears that the Neldon surname is a variation of the German surname of Nulton.In "Bucks County, Pennsylvania Church Records of the 17th and 18th Centuries Volume 1, German Church Records" by F. Edward Wright, there are several baptismal records for children of John/Johannes Nulton and Maria Eva "Eve" in the Nockamixon Reformed Congregation and the Tohickon Union (Reformed)church records.
In Nockamixon records:
p. 69 Johann Henrich of Johannes Nollten and Maria Eva, b. December 25, 1778; bapt. March 11, 1779.Spon:George Fuhr and Maria Eva.
p. 92 John Christian Noldten of John Noldten & Eva, b. Dec 19, 1780, bapt. Mar 25, 1781.Spon:Christian Drager & wife.
p. 93 Michael Noldtin of Bernhard Noldtin & Maria Eva, b. Dec 9, 1782, bapt. Apr 2, 1783.Spon:Christian Ruth & Maria Sarah.
p. 96 Catherine Nalten of John Nalten & Eva, b. Oct 29, 1784, bapt. Jan 23, 1785.Spon Michael Fur & Catherine Reimer.
In Tohickon Union records:
p. John of John Nolten and Eva, b. August 30; bapt. October 10, 1773.Wit:George Fuhrer and Eva.
Given all the sponsors named Fuhr (and variations of Fuhr), it seems likely that Eve's maiden name was Fuhr.