OTG, besides being lazy, what keeps me from commuting is chores.
I have to go to the postoffice, get the car fixed, go to the doctor.
so I do what you are proposing, commute 2 or 3 times a week (maybe starting next week, it's getting light enough finally!) and do all the chores that require a car on the other days.

If there are a couple scary intersections, why don't you just walk across them?
I find that if i put my bike IN THE CENTER OF A LANE at an intersection, clearly showing my intentions, I usually do fine.