We are leaving from Westchester County, NY for Boston. Unfortunately,we can not leave until about 6pm on the Friday of Memorial Day Weekend! Intended route is 84E to 90E into Boston. I am concerned that this will be a traffic nightmare. Does anyone have any good alternatives? We could: 1) go half-way Friday night and drive the balance early on Saturday, 2) leave late Fridy night - but how late would we have to leave to avoid heavy traffic? or3) just wait and leave early Sat., but then lose some of our vacation time in Boston.

Your ideas and opinions would be great to hear!

I really think you're overestimating the traffic. I doubt you will have any problems. One, your leaving after rush hour - especially Friday's and Holiday weekends, rush hour starts about 2:30. The time you would enter the Boston area should be free and clear. Anyway, you'd be headed opposite the traffic - people will be leaving the city, not going in. You wouldn't enter Hartford until about 8:30, so that shouldn't be a problem either. You may hit some trafic in NY, as people will still be exiting the city, but this shouldn't add too much time to the route. Again, I think you'll catch the end of rush hour at that time. I think your leaving at a great time to avoid most of the traffic. If 90 concerns you, you could take 95E/128 through CT & MA and pick up 93 just outside Boston to get into the city. It's the long way around and I don't think it will save you any time. Either way you should get into Boston about 10:00 p.m. I wouldn't consider splitting it up between 2 days.

You're going to hit some traffic no matter which way you go, but it shouldn't be anything close to the nightmare called Thanksgiving weekend traffic. 84 to 90 is definitely the best way. The alternative that worldexplorer suggests could be worse!
I'd say, "Stick to your original plans!"

If you were to leave around 7PM on Friday you should avoid most of the heavy traffic. I would drive all the way. If you don't run into any major delays you could be in Boston around midnight

I've done this trip on other holiday weekends (but not recently on Memorial Day) and I think that leaving at 7pm is still a little early.
If you're in Westchester, that means you still have the bulk of the people who have left NYC right in your backyard! I would seriously consider leaving even later-- 8 or even 9pm, if you can stand it.
I tend to choose the leave very early on Saturday option. Yes, you sacrifice some time at your destination, but if you leave early enough (6 or 7 am) you can breeze through traffic, and end up starting the day just as if you had arrived very late the night before.
Let us know how it goes--I'm headed out that way later this ummer

Thank you for the suggestions. I am still trying to figure out which option will work best. I will keep you posted.