Can you really do your crabgrass pre emergent in late May? Cold in Maine but...seems late.
Talk to more people...more fert dealers...more university people. Normally your crabgrass control has to be down by the date of the last frost in your town. If it takes 3 weeks to cover all your lawns--you need to start 3 weeks in advance of that. Look for local soil temp average records. Crabgrass control should be down before soil temps hits 55 degrees. Some people say apply crabgrass control about the date of the first mowing--or before. (Northern grasses.)
Your fall fert and blanket herbicide should be between about 2 weeks before and two weeks after the first frost in the fall. My opinion.
Remember you are not allowed to apply 2,4-D more than twice per year.
There is time enough for 5 applications if they are 5 weeks apart.
Optionals include grub control, lime, seed, aeration with seed, organic fert applications.