Hi Melissa, Doverhill is in Martin Co. IN, and Benjamin and Prudence McCAUSLAND appear in Martin Co. in the 1860 census, but not in 1850. So I'd say they definitely moved there with her parents Lewis and Prudence SANDERS. Are you aware that Lewis SANDERS' brother Edward married Mary McCAUSLAND of Washington Co. PA in about 1808? Mary was the daughter of George McCAUSLAND and Catherine KIDD. Edward and Mary McCausland SANDERS had two sons before Edward died during the War of 1812. Mary, the story goes, then married a McCAUSLAND cousin. I suspect that Benjamin McCAUSLAND who married Prudence SANDERS was from this same family of McCAUSLANDS who came from County Tyrone, Northern Ireland, and settled in Washington Co. PA in the 1780's. Benjamin says in the 1860 Martin Co. IN census that he was born in PA. He appears to have died between 1860 and 1870 in Martin Co. IN. Many years of Martin County censuses are online; Here's what I found:
1860, Perry Twp, p. 792: McCAUSLAND, Benjamin42carpenterb. PA1000500 Prudence39---b. VA next door is: SANDERS, Matilda15---b. OH (age questionable) James25laborb. OH (may be John's son)
1870, Center Twp: McCASLAND, Prudence45b. OH(wrong state)
1880, Dist. 157, Center Twp, p. 395A: McCAUSLAND, Prudyselfwidowed59 OHk. houseVA VA Attiedausingle5 IN---OH OH
Either Attie is not 5 (born when Prudence was 54!}, or she is not a daughter but a granddaughter. It's possible there could have been a child who was married and gone by 1860, but no children of Benjamin & Prudence show up in the censuses. There are no other McCAUSLANDS in Martin Co. IN in 1860, 1870, and 1880.
Information about the McCAUSLANDs of Washington Co. PA is hard to come by, and I have two family lines, SANDERS and CONN in Brooke Co. (W)VA, which connect to them as well as to each other. So, like you, I'd like to know more about them.