I assume from the dates and location that your Lucy Green is the same person I found living in So. Canaan in 1824.
I have no other information on Lucy. I cannot put her in my lineage as I don't have a common ancestor identified as yet. From my posting you can see that I have also reached a dead end with my great grandfather (Lawrence) who immigrated and farmed in Cornwall.
Perhaps if you can give me some information on how your ancestry gets to Lucy I can see some pattern, someone who may be a common ancestor.