Hello and thank your for helping me plan this trip of a lifetime for my family.
(I looked for this topic but didn't find it and I apologize in advance if this topic already exists.)

Here are the details of our trip:
My husband and our 3 sons (11, 8 and 6) would like to make an RV trip to the Western National Parks this July, 2011.
We live in the Washington, DC area and plan to fly out West and back and pick up our RV out there.
We have 7-10 days.
We would like to visit any and as many of the following: Bryce Canyon, Grand Canyon, Grand Tetons, Yosemite, Yellowstone, Zion.
We would like to travel beginning July, 2011

Which itinerary would you recommend?
Which city would be the most practical and cheapest to fly in and out of?
What size RV and which rental company do you recommend?
How far in advance would we have to make camp ground reservations?
Is it worth it to book through a travel agent or can I do it all myself?
What have I missed?

Thank you all for taking the time to reply to my message and happy holidays to you!