We drove the coach up from SC the last week of March. The Tappanzee is very easy. I would not suggest going any further out of the way than that. It's just unnecessary. If you can time NYC for the very early morning hours on a weekend (before 6am), I would not hesitate to go over the GWB. Done it before and it's fine.
I honestly think your worst section will be in the New Haven CT area, where the road is undergoing major construction. Very slow, narrow and twisty areas. seems like it's becoming CT's version of the Boston "big dig".....