OP here, I did a partial commute this week. I almost didn't do it as that day I was in an all day meeting with customers. Then I figured there would always be some reason not to and just did it. I spent some time and money beforehand gathering equipment and getting the bike ready. Head and tail lights, reflective vest, new tubes for each tire, reflective tape on frame, etc. I cleared a secret bike storage location with the Facilities manager at work, and there is a shower at work if I really need it.
Conditions: 30F and dark riding there, 45F and sunny on the way back, roads and bike paths clean and dry after a recent thaw. I drove 14 miles, parked, biked 7 miles, changed, worked all day and rode/drove home.
Observations:
1) I'm out of shape, it took a long time, and I was sore. This is why I want to do it more often, though.
2) Cresting a hill is sometimes a triumph, sometimes a disappointment, depending on if you meet a 20mph headwind
3) I got the timing and clothing/layering mostly right, pit zips are good.
4) This takes a lot of planning. As much as I planned ahead, I accidentally brought my laptop home from work the night before (force of habit) and had to store it in a backpack for the ride in, along with extra clothes. My laptop is heavy.
5) My car is amazing! I just press very lightly on this little pedal and it zooms up giant hills amazingly quickly, with no additional effort from me. Those hills that I used to think were small and insignificant are only truly so to a beastly metal and plastic contraption which contains constantly exploding, highly-refined ancient sunlight.
6) I really enjoyed it! I think it is way more satisfying to me knowing my biking is a partial commute, rather than commute by car and ride before and/or after work.
7) I could see it being scary or uncomfortable if the paths/roads are covered in snow/slush or some other condition that would make it slippery or reduce visibility to drivers who aren't expecting me to be there.
I'm going to keep after this and see where it goes. I can see maybe doing this 2 days per week, more would be difficult just due to the time required, and the distance I cover can increase as I get quicker. At the recommendation of a MMM forum member I started body weight training for fitness when I have less time or conditions make a bike commute scary.
As for my original question, I'm not pursuing the ebike or going down to less than 2 vehicles for the family. The partial commute seems to be a promising balance to get some fitness in and feel productive during biking (going somewhere I need to go) while keeping it safe and having flexibility to choose when and how far I bike.