New York Washington then west side loop in a month - please help

My husband, eldest daughter and I are meeting our youngest in New York in September, on her way back to Australia after teaching in England since Feb 08 and have planned the following. Please give your thoughts. I know we'll be on the move but want to make the most of our trip. Have already booked the flights to take advantage of cheap deals from Australia!
6th Sept - Meet in New York
11th Sept - Drive to Washington DC via Baltimore and Philadelphia, staying somewhere along the way
15th Sept - Drive Washington to New York via Pennsylvania staying somewhere around Lancaster; maybe Bird in Hand?
16th Sept - Return car to JFK and fly to LA
19th Sept - Drive to Williams
20th Sept - Drive to Grand Canyon for the day and return to Williams
21st Sept - Drive to Las Vegas
23rd Sept - Las Vegas to Yosemite
24th Sept - Drive to San Francisco
28th Sept - Drive south, stopping Monterey (other suggestions)
29th Sept - Continue to Los Angeles
3rd Oct - Leave bound for Australia.

As I said the flights are set. Can I have your feedback please - I've not used the RTA forum before. THANK YOU from Down Under.

Welcome aboard the RoadTrip America Forums!

I'm not exactly sure of the timing of some of your drives, so many of my comments will be conditional on what you actually intend to do. Your description focus, for example, on cities, but much of the best of America is in between in quieter, less urban settings. So on your drive from New York to Washington, I'd suggest that you plan on spending the first evening in Philadelphia, see the historic sites as well as Elfreth's Alley and the 9th Street Italian Market. Then the next day get a taste of something entirely different by driving south down the peninsula between the Chesapeake and Delaware Bays and visit some smaller quaint towns such as Chesterton, Easton, Oxford and St. Michael's, and then cross the Bay Bridge to Annapolis, another great town for walking through before continuing into Washington.

On the way back up to New York, you can see Baltimore and then heading around Philadelphia to the west and north. If you want to see Amish country, just wander some of the smaller roads in an area defined roughly by the towns of Lancaster, Oxford and Downingtown, but keep in mind that the Amish don't 'sell' themselves. The roadside Amish attractions almost certainly have little that is authentic about them. Rather than Bird in Hand, I'd suggest Lititz as a cute town to send the night in. then the next day you can continue northeastward in Pennsylvania to East Stroudsburg and visit the Delaware Water Gap before finishing up back in NYC.

The west coast portion of your trip has been discussed in great detail elsewhere, so be sure to read those posts for more details.

AZBuck

Thank you for your reply AZBuck! That is exactly the type of information we need. Your suggestions sound really good. While we want the girls to experience the major cities we mentioned, we also want to see smaller places as well - it's often these little towns that hold the most special memories of a trip. They also don't get a mention in guidebooks and so we miss them! Have located all the places on our map with the exception of the Delaware Water Gap - where is that?? Could you tell me a little about it?
Thanks again.

The Delaware Water Gap is between where Interstate 80 and Interstate 84 cross the Delaware River between New Jersey and Pennsylvania.