You know it's funny I suggested my favorite places to visit and forgot my hometown San Diego is a beautiful place to visit. Since swimming is not necessarily a priority for you our beaches are wonderful this time of year almost always warm enough to walk along and not crowded.
Other things to see Balboa park, San Diego Zoo, Cabrillo national monument, Seaworld just to name a few. head to Ocean Beach and many antique stores on New Port ave. or wander further east to La Mesa and the many antique stores and cute little quilt shop If you tire of the coast an hour away is the small mountain town of Jullian or venture further to the borrego desert.
Do you want to visit quilt shops? From our north county to the east county and into south county there are 12 or more shops most of them worth visiting...you could do it in a day but you would be exhausted I would take 2.