Hi Miriam:
You've laid out a good plan for estimating time. Another aspect is the content.
I start with the student learning outcomes (SLO's): What is it that the student will need to walk away from this course with? By beginning with these, all pathways in the course will feed into the SLO's. Once the SLO's are set, course planning such as you described can be conducted with the reasonable hope that the course will meet the desired learning objectives.
Regards, Barry
