That's very cool but don't see how it's possible.
There is no golf course I'm aware of near mass transit. And even if there was, I wouldn't want to carry my bag and shoes all that way.
What about going to the beach? Or going away for the weekend?
Costco?
My daughter's school is not near a subway or bus line.
Her rowing regattas are not near mass transit.
Son's swim meets, soccer and basketball games, boy scout meetings.
The supermarket. The hardware store. Etc. Actually I can't think of a darned thing I can get to without taking the car.
Well for one thing I'm single (always have been) so no family transportation issues. Here in south Arlington I have most of my necessities - food, bank, drugstore - either within walking distance or right on the way home from work (our neighbourhood Giant re-opened a year ago, and there's a Harris Teeter at Pentagon City right on the way from the Metro station to where I pick up the bus). Getting to and from work is very easily accomplished with Metrobus/rail. (You mention Costco - there actually is one near Pentagon City that I could join if I wanted to, but haven't given it any thought - the aforementioned grocery stores fill the bill.) And of course getting to/from Nats and other sporting events just takes Metrobus/rail, except for certain trackwork weekends when I just sell the tickets.
As far as leisure time, I'm not the outdoorsy (camping/active-weekend etc) sort (specifically the thought of spending a weekend in Ocean City holds no allure for me whatsoever) - vacation time for me means Europe, most often London, where for the most part one does not need private transportation of any sort.
I'd be less than truthful if I didn't admit that the lifestyle choice does have its limitations - never getting to see the Baseball Hall of Fame or the Grand Canyon for instance, or visiting Hawaii again where I lived in the early 70's (in fact not driving pretty much puts the whole USA off limits, with the ghastly airfares and poor transport infrastructure, and the fact that most American cities have little, if anything, worth visiting) - but these do not, in my opinion, justify the hideous expence, hassle and risk of driving in this area.
One further consideration: I do drink a lot.
But don't let anyone say that a car-free lifestyle in this area is impossible - it is VERY possible - I've been proving it for over 30 years.