On the off chance that no one has answered you yet, you need to get yourself a copy of "James Ludden and Descendants", by Wallace Ludden. The book doesn't have much information on Ruth (Wallace didn't find any of Ruth's children), but it goes in exhaustive detail up and down the rest of the family tree.
Here's a quick summary:
Ruth was a 6th generation Ludden, and was born 12 Nov 1772; mar. Ebenezar Crane, born 23 Feb 1766; died 1 Oct 1836.
Ruth had three sisters: Sussana (b. 20 Aug. 1768; mar. 21 July 1787 Benjamin Wales), Joanna (b. 31 Jan. 1770; mar Wm. Bowditch; d. 8 June 1830/31, buried in Village Cemetery, Front St., Weymouth), and Abigail.
Ruth was the daughter of Benjamin Ludden (b. 2 March 1746) and Ruth Allen, whom he married 23 Oct. 1767 (or 66). It is possible that Ruth Allen Ludden was a widow in 1777.
Benjamin had eight brothers and sisters: Seth, Mehitable, Mary, Thomas, Joanna, Micah, and Abigail (?). I'm descended from Benjamin's brother, Seth.Benjamin's father was also named Benjamin b. 25 Nov 1719 mar Joannah Wales, b. 6 Jan 1720, dau. Joseph and Mehitable (White) Wales ).
This elder Benjamin (referred to as Benjamin ter in the book) was the son of Joseph Ludden, born 1690 mar. 9 Jan 1716/17 to Dorothy Thayer (b. 1692, dau. Nathaniel and Hannah (Heyden) Thayer)
Joseph's father was another Benjamin, b. ~ 1650, mar. ~1678 Eunice Holbrook, b. 12 Mar. 1658 d. 1716 dau. Capt. John Holbrook and his 2d wife Elizabeth (Stream). Benjamin "enlisted as a soldier against the bloody French and Bloudy mutherous and Salvauge Indians," and was killed in 1690.
Benjamin's father was James, the ur-Ludden, b. 1611 "and possibly one of a party from Weymouth, Dorsetshire, England that settled in Weymouth Massachusetts in 1624." He died 7 Feb 1692.