I put 1990s because I assume she didn't there till there was a realistic plan and prospect of releasing the Master. I can't visualise her tying herself to a one-horse town with way too much sunshine for decades before that. She may well have visited the Master before he was incarcerated, but I think she's much more likely to have roamed world troublespots, making temporary alliances with other vampires but never allowing herself to get close to another. I can certainly envisage her active in the Spanish Civil War, Nazi-occupied Europe, Korea etc.