I’m curious, has anyone ever tried playing through a campaign set during the Saxon timeline? Otherwise known as The Year That Never Was? Could even be considered an alternate timeline story if you don’t want to alter continuity. Would be rather interesting for any Time Lord PCs if they fall into the Master’s hands.
'Twould kinda suck knowing everything you do is going to be wiped out in one year.
Unless doing just that IS your goal.
I think it might be more fun and interesting to do something similar that they players don't know about in advance. Then you can get maximum effect out what happens, since you (actually the heroes) are going to reset the timeline later. Kinda like what the series did in "Turn Left" or "Father's Day".
Considering that a good portion of major events happening to Earth in the series get timey-wimey retconned out of existence every so often, this sort of thing is probably happening quite often.