Ah yes, you were coming up from Palatka, now I remember the conversation!
Alligator Farm, Lighthouse, Sunday lunch at the Conch House with live music (if it is calm you can dinghy around), take it a show at the amateur Limelight Theater
https://limelight-theatre.org/ , visit the Lightner Museum, ride the trolley, if you like golf Uber over to the World Golf Hall of Fame, Walk down to Sailors Exchange and see what you can find (Uber back its a couple of miles)
https://www.sailors-exchange.com/ , go over to Anastasia Island and walk the pristine St Augustine Beach. Vivt Flagler College (our daughter went there!). Lots more. Heck I think the Jags have three home games in December that you can come spend a fun day at! Also check out the happenings at the St Augustine Amphitheater - they always have stuff going on.