Hello anybody and everybody!

It's a way off yet, and still in the deciding stages really, but I am comtemplating an American Road Trip.
Possibly 4 - 6 weeks long, I would like to fly over from London and hire a car with a friend and explore.

Now...I have never done this before and know nobody else who has either. So where do I start?!

I know I would like to visit Maine, Boston, Lake Michigan, Washington DC and Chicago. I would also love to see Houston, Dallas, New Orleans; as well as San Fran, LA, Las Vegas.
So where do I start planning? What is the best way to do all of this? When is the best time of year to visit these places?
I don't want to be driving the whole time, as I'd like to stop and see things too, but I am aware these 'three' areas are 1000s of miles apart! So would you hire a car at each location but fly between them?

Anybody with any ideas or experience or advise, please let me know your thoughts.
Maybe 6 weeks isn't long enough and I should cut my route down.

Let me know what you think!

Thanks

Peace out.

Judi-mae
xx