Where to stay in LA ?

[Infinity Red]

Hi my daughter and her two friends will be arriving at Union Station from San Diego in July for four nights.
They've no idea where to stay, they'd like to see Santa Monica, Rodeo Drive, Hollywood walk of fame, Sunset Boulevard and Venice beach.
After four days they'll be flying on to San Francisco, I'm assuming flying is better, no idea where they are in relation to one another
So where in LA should they stay, they're on a bit of a budget too , many thanks.