Capitol pushed the Beach Boys for too much material in too short a time for the group to maintain as much quality control as would have been desirable.
Consequently, most of their pre-1965 albums contain a high degree of filler, and thus stack up poorly next to those of such contemporaries as the Beatles, who were able to maintain high standards on almost all of their tracks.
Surfer Girl does have some great tunes, including the title song, the hot rod ditty "Little Deuce Coupe," and "Catch a Wave" (which could have been a substantial hit single on its own merits).
Most significant of all is the gorgeous ballad "In My Room," which anticipated future Beach Boys releases both in its sophisticated production (strings, organ, dense harmonies) and its personal, solipsistic lyrics.
The rest is surprisingly mediocre filler, especially as at this point they were restricting their lyrical themes to beach culture almost exclusively; "Your Summer Dream," with its unusual harmonies, is about the most interesting of the obscure tracks.
If you're not a dedicated Beach Boys fan, though, you should pass, as you can find the first-rate tracks on best-of anthologies.