Boy picked a bad week to visit... major wildfires in the area have affected air quality. it's extremely poor right now and temperatures are very high. The only recommendation I can give you is stay near the beach cities, preferably Orange County or San Diego. If just looking for cruiser bikes, many sea shacks in Huntington Beach rent them. If you are looking for nice road bikes, check out Laguna Cyclery. Mountain Bikes, The Path in Tustin. If you rent from Laguna, the shop guys can give you route information. You can also go to bikeirvine.org and check out the listed route slips. Again something with Pacific Coast Highway in it is best.