There are a bunch of wineries in Temecula valley, which are most accessible with a car. The link below will show you a list and map of the possibilities. Be sure to plan/call ahead in case some of the wineries require reservations.
If you have some extra time during your stay in Murrieta, Santa Rosa Plateau has beautiful hiking trails that are free to all!
There are multiple food options and shopping at the Promenade in Temecula (the city adjacent to Murrieta).