I too have been dealing with a lot of connection errors, however I've always had really slow internet. The crashing problems is a tad odd, considering you're usually in the game and then it crashes after a bit. And then the part with the freezing and all that.
DO you have an older computer by chance maybe? Or just have too much on the memory drive? I've heard that sometimes an older computer or one with less memory room can effect the game.
You can also do what a lot of people do, and that's change your rendering system. Sometimes that solves the issues.
In that case, I would go ahead and try changing the rendering system to see where that gets you. I also forgot to ask,
have you downloaded a lot of mods? Or do you use the preset sync perhaps?