I sold my FW on FB marketplace. She already has an account, so it shouldn't be difficult. All of the usual sales cautions apply: Meet in a public place (some police stations have an area specifically for this type of transaction, which is great); I went to a local library after calling ahead to make sure there was a place we could have a table near an outlet for her to test it.
Alternatively, I have seen little postings at some quilt shops. Perhaps check with some of the local shops? Or, even if she isn't active in a guild, does she have any contacts who still are? We've had folks mention stash sales of former members, so would guess that they would be willing to do same for a FW.