First of all, as a fellow remote worker I know exactly what you mean by wanting to get out there and see some people for a change haha. Anyway, I lived in Boston for a year after uni and I really enjoyed the Pavement Coffeehouses. Look them up, they have a few locations around the city. They're a bit artsy but not too much so. Also, the 1369 Coffee House (that one also has several shops) is amazing if you're a coffee fan - they have tons of amazing brews from all around the world! Those are the main two I could think off the top of my head but I'm sure you'll find a bunch when you just walk around.