My commute is just over a mile, if I take the most direct route. I either walk or bike, and have done so for 15 years.
Mostly, I absolutely love it. But I have to say that it gets tough to stay excited about it in the dead of winter. Like when I leave the house at 5am in the dark and it's 10 degrees. Yowser.
As far as losing weight--since my commute is pretty short, it's not really helping me lose weight. (But considering all the exercise I have gotten by commuting by foot or bike for 15 years--I'd imagine that it has had a huge (positive) effect on my overall health.) If I am in walking mode, I will often choose a longer route, just to get more exercise. (Several years ago, I lived across town, and mostly walked to work. It took me 45 minutes each way. It helped me stay very trim!)
If I were to be wimpy and drive to work, I would have to buy a parking pass for the day, which recently went from $2 to $3. To a non-Mustachian, that wouldn't seem like much, but to me, I HATE spending that money!! (I could buy a parking pass for the academic year for $110, but I haven't purchased one of those since my first year of employment there--before I knew any better.)
I am lucky, in that I have several options for commuting to work. I can walk, choosing from about 5 different routes, most of which are combos of roads and trails. I can mountain bike, choosing from 3 different routes, involving roads and trails, or I can road bike, choosing from 2 different routes. Sometimes, if I have time and extra motivation, and if I am on a bicycle, I will dump my backpack in my locker at school, and then head back out on my bike for more time in the saddle before I hit the shower.
It's quite a solitary experience, but I am single and live alone, so I am kind of used to that. Occasionally, I feel a desire to chuck all of this craziness and just commute by car (stopping for a great cup of coffee on the way) like all of the other "normal" people. I also get a bit tired of all of the packing and unpacking that goes with creative commuting. (In the early years, it took me a while to get my system down. I now have lots of school clothes and school shoes in my office, a stash of fresh towels and undies in my gym locker, etc.)
Another frustration I have is that more of my colleagues don't creatively commute. Instead, most of them buy their parking pass, drive their clown cars--most often, with just the driver in it--stop and buy coffee en route, and then stress out about when to find time to go (by car, of course) to the gym for their exercise.
I have a fantasy that one day, instead of my campus consisting of 95% cars and 5% bikes, that the opposite would be true. Just trying to picture that is really amazing!
Back to your questions--I did not ditch my car. I have a 4WD Toyota Tacoma that has been paid off for several years. I use it mostly to drive me and my hockey gear to the ice rink in the winter, and to access the mountains for camping and hiking in the summer. (I am considering getting a trailer for my bike so that I can bike to and from the ice rink.)
Sorry if that was more than you wanted. I hope you stick with it for many years to come!!