It's about the 50 - 60 hour mark when the game starts to mess up, so expect complaints to come rolling in by next week. I've had one full crash as well, near Boston Common. I recorded it on my Xbox One, so it'll be on my Profile somewhere. Luckily I save often (turned off all Autosaves bar the Pipboy Autosave which is set at 60 minutes).
Yeah, it lags up pretty bad in central Boston and when travelling to any built-up settlements. The draw distance ends up being fairly bad too with lots of pop-in (more like "fade-in"). Overall, it's currently been tagged as "like New Vegas" in my mind, which is to say, everything works great until you hit an almost arbitrary time limit, then it starts going downhill. With patches, NV was arguably the most stable "Bethesda RPG" (I know, it was developed by Obsidian, but I'm using "Bethesda RPG" as an adjective to describe the style of the game) I've ever played. The Rift/Lower Eastmarch still gives me trouble in Skyrim though, as does outside Vault 3 in New Vegas and numerous places in FO3. I'm hoping, that in 2 years time, these issues with Fallout 4 will be resolved. I don't regret buying the game on release or getting the season pass, Bethesda earned my loyalty through making exemplary games and experiences and I'm thoroughly enjoying Fallout 4; but there's always that niggling doubt at the back of my mind, gnawing away, making me wonder why these issues (some of them glaring) are missed in the QA testing and whether I should continue to support a company which some would argue "release broken games" (irrespective of scope, it does appear to be an unfortunate trend and almost bad habit now).
I guess my opinion and my trust will ultimately be shaped and determined by whatever Bethesda choose to do about these issues. I just hope they keep watching all of that game DVR footage from the Xbox One users. I have several friends who are starting to run into issues, so it won't be long before it hits these forums. Most people are trying to remain optimistic for the release week, as am I.