There is one genealogy that has Alanson Titus (b. ca. 1784 at Hinesburg, Chittenden Co., VT) as the son of John Titus who married Polly Lloyd. That John Titus (generation 6) was the son of Ebenezer Titus and Mehitable Garnsey. It appears that that John Titus and family remained in Rehoboth, MA and there's not much if any, of a VT connection. That genealogy was authored by Richard Lyle Pettit, in which he states "The children listed as John Titus' are taken from the Rev. Pen application of John Titus. There is no proof that this John is the father of the John applying for Rev. War Pension except his age."
On the other hand, we have John Titus (generation 7, b. Oct. 28, 1863 in Rehoboth) the son of the previous John and Polly Lloyd. He enlisted from Rockingham, VT in the Vermont Rangers and was given a Revolutionary War pension. Here is the VT connection and the reason why I believe Alanson is the son of John and Metitable Fuller, rather than John and Polly Lloyd.
Admittedly, Alanson would have been born (ca. 1784) before the marriage of John and Mehitible Fuller (Jun. 15, 1786), but that was not unusual in those times. Further research should be done on this, but in the meantime I'm sticking with Alanson as the son of John and Mehitible.