Strangely enough, there appear to be some Roydhouse/Roodhouse entries in the IGI. I never fail to be amazed at some of the surnames I've come across since I've been doing FH!!

As the 1812 marriage entry didn't say whether Elizabeth was a spinster or a widow, but
did say that Luke was a widower, it's probably a safe bet to deduce that she was a spinster.
Have you seen this IGI entry:
1782 Hedon born 2 Sep/bap 3 Sep Betty d/o Daniel John Roydhouse & Ann?
That would make her 30 when she married Luke - how old was he? Did they have any children called Daniel, John or Ann?
Jill