IIRC, East to West goes against prevailing winds. That could get old pretty quick, once you're over the Alleghenies (or whatever they're called in VA/WVa/Eastern Ohio. Of course, if you start in RI, you can't bicycle very far if you head East.... If you've pedaled mainly in the East, you're probably good with hills but may not realize how debilitating riding against the wind is, at least to many people. And hill training doesn't help with wind, IME.
How much time can you take? When do you start? What support will you have?
Sounds like a great trip in any case. Best of luck. I wish you light winds, pleasant temps, and rain only when you're sleeping.
Believe it or not, I used to ride all over the East Side of Providence, College Hill, Federal Hill, down to the Seekonk River, East Providence to Newport ... long time ago, though. When I walked around College Hill last year for a couple of days, my legs got sore. I can't do hills, now, but I can do (some) wind - hills are more fun.