Sticking to the calendar

Last year when we went through this month I did a project and got through 90% of it and stalled. This year I am committed to meeting my goal and while I see the value of putting everything in the calendar including the steps towards my goal, time off, family things etc. the place I struggle with is when it comes to being exact about how my days look (family time etc.) My husband’s job often pops up with an emergency meeting or last minute trip that we don’t know about until a few days before and it causes me to rework the schedule all over again which takes more time than I really want to be spending redoing a months worth of calendaring.
In this case would it be better to just do plot out my project steps for the month and then calendar everything else at the beginning of the week (like family stuff, self-care time etc.) or would you still do an entire month and then have to shift everything around?
Thanks for the advice