San Diego, Ontario, and John Wayne are all about an hour away from Murrieta and Temecula. We'd highly recommend renting a car, but you can also take an Uber/Lyft/Taxi for ~$100.
This depends on how long you're staying and the experience you're looking for. If you're wanting to stay as close to the wedding venue as possible, we'd recommend staying in Murrieta. If you're setting aside a long weekend to enjoy food and wine, we'd recommend staying in Temecula but allotting 25 minutes to drive to the wedding. If you stay in Temecula, we recommend staying at a winery to get the full experience and most wineries include daily tastings and a complementary bottle of wine (!)
In order to allow all our wonderful guests, parents included, to have an evening of relaxation, we have chosen our wedding to be an adult only occasion. We hope this advanced notice means you are still able to share our big day with us and will enjoy having the evening off!