Barbara went to a junkyard to find Susan, afraid that Susan was either being ravaged by her old man or that Susan was ravaging a young man, in which case, Barbara wasn't getting any, so Susan shouldn't either. Fortunately, they found no paedophiles (the Doctor is not a pedophile, despite what other entries may say).
Unfortunately, she and Ian Cherryton were kidnapped, because although the Doctor is not a child-diddler, he is often a complete ass at times. In the journey to find the lost episodes of Who, she's been assaulted by a giant pepper-pot, ran down a pepper-pot with a truck (should have learned to SPLINK, silly pepper-pot), tried to change an entire entrenched culture of sacrifice by proclaiming herself a goddess (which went about as well as you would expect), kept herself from strangling Susan (we love you, Susan, but you really do need to get your ankles checked) and kept the boys in the TARDIS in line. Also, she probably shagged Ian at some point.
Her time on the TARDIS lasted from An Unearthly Child up until The Chase, where she and Ian realised that Hartnell would never be able to get them home due to his dementia, so they told him to go fuck himself, took a chance and piloted a Dalek time machine home. According to some SJA episode set in 2010, they hadn't aged since the 60s for some reason, but you should treat that line like you treat the half human fiasco.
Barbara was famous for having the most comforting bosom in all of spacetime, which Susan availed herself of regularly from early in the second episode of the series up until her departure. Sadly, Ian never got a chance (at least on-screen—but check him out at the start of The Romans, and guess where that grin came from).
Not half as hawt as the lady who played Hill in An Adventure in Space and Time, though.