Hi I am travelling from east coast for 8 days trip to west. Landing in sfo flying back from LA. planning on sfo,la and yosemite. I still have 2 days left in my itinerary. would like to add lake Tahoe or death valley which is better and worth seeing ? I am planning end of Aug. I know both places are different but as I cannot do both at least I would like to visit one. We r couples with 2 kids 6 & 9 yr old.