I mean that's the main plot line.
What you should be doing is laying out a scenario. For example, instead of saying "Health Problems cause Ronald Reagan not to run for the GOP nomination in 1980 which leads to Jack Kemp former NFL star and congressman of New York to upset George Bush and win the 1980 election," you say "Health problems cause Ronald Reagan not to run for the GOP nomination in 1980 which leads to Jack Kemp contesting the 1980 primary due to his absence. Does he come out on top?" Or something equal. Half of the entertainment of reading a timeline (which I actually haven't done in quite some time!) is not knowing what's going to happen.
If you already say what the outcome of a timeline is, it takes the suspense and fun out of the whole thing.