I would say around 4-5 days. So in that context Scott's death isn;t really that early. Jean's only a couple of days behind him.
DAY 1: Hank talks of Cure, Scott goes to lake and dies. Mystique frees Juggs. Tells of Cure.
DAY 2: Jean found at lake, leaves. Followed to her home. Xavier dies. Iceman and Pyro at the mutant cure clinic. Mystique captured and cured.
Day 3: Jean with the brotherhood in the woods. Iceman with Kitty iceskating.
DAY 4: Golden Gate. Alcatraz
DAY 5: memorial for fallen heroes