Boston is extremely walkable, it's a relatively small big city and most of it was built before cars. I've got a picture of my old apartment building with dirt streets and a horse carriage out front. I used to regularly walk from one end of the city to the other for leisure. The T is surprisingly good public transit for america too. They've even been doing free fares on some of the bus routes for the last few years, and just extended that experiment because it was pretty successful.
People drag it for not being a grid sometimes (the "paved-over cowpaths" myth) but that's because the streets go around hills since they needed to be traversed by people and horses.
Oh my God my partner and I recently looked at a bunch of cities to decide where to apply for jobs, and we were fucking floored when we saw how expensive Boston was.
Why the fuck is rent more than NYC and SF??? It was literally over $1000 more per month than the other cities on our list including DC, Seattle, and Chicago.
So the thing with the Boston rental market is it depends on what time of year you're looking. Like 75% of Boston leases open on Sept. 1 and end on August 31. Most apartments come on the market for the current year in the first 3 months of the year (Jan/Feb/March) so if you're looking outside of that time window there's much less available and the prices are higher.
Edit: There's also no rent control which helps nothing
Seattle's downtown, Fremont, and Ballard neighborhoods. But be careful because each of those extend past the walkable area (like Fremont and Ballard extend past their walkable area and include straight up suburbs).