Old Town Temecula is super walkable, essentially one main street of food/bars/shops. Great for people watching- you will certainly see your fair share of wedding guests and bachelorette parties.
Listen, you can go wine tasting at any of the 47 wineries in Temecula and it will be fabulous. Enjoy and take home a bottle! Rec'ing Callaway because it has nice views and sometimes live music.
Lorimar has a fun vibe, live music, great lunch spot.
You might just run into one of the groomsmen on the casino floor!
If you feel called to catch some ocean views before heading home, Sunset Cliffs are the place to go.