Barnsdall is the best! I second this as a great solo stop. (See the art gallery and Hollyhock House first, then break out the picnic blanket.) Factor in the Friday wine tastings, either to get a ticket beforehand or avoid. But there really is nothing better than relaxing on the lawn at sunset. Skylight Books and Blue Rooster Art Supplies are nearby if you need a book/sketchbook to spend even more time up there.