The Big Finish stuff isn't generally considered canon. However, it was stated on screen around the 50th or sometime during Capaldi (my memory's fuzzy,) that during the war Rassilon and the high council recalled all the Time Lords to Gallifrey to fight. Considering they even recalled banished evil Time Lords like the Master it's been considered to imply that Susan would have been recalled at this time.

It can actually be argued that she must have been in order to reappear the way she has still in her Carol Ann Ford regeneration as the last time we saw her was on Earth in 2160something without a TARDIS, and it has been stated that The Doctor never went back for her. So, easiest non-canon explanation is that the Time Lords retrieved her to fight, to be a hostage used to compel The Doctor to fight in the war, or a little of both. She could have then left again as a rogue in the brief period between the planets resurrection and destruction, somehow, escaping its fate as The Rani clearly has.

I know math (or maths) is/are hard, but Karen Gillan hypothetically returning in 2062 would be only 52 years between first and last appearance and thus a decade shy of the record. Besides, a better comparison would be Billie Piper starting with the premier of the revived series in 2005 and which would result in a hypothetical return in 2067 to meet or beat Carol Ann Ford's record.