We've done the East Coast and it was amazing. We spent just over a month there.
We booked via Trailfinders who I can't recommend highly enough. We went in, told them what we wanted, where we wanted to go, how we wanted to travel and came out with exactly what we wanted at a fraction of the price if we had done it ourselves. We booked train tickets and car hire through them and some hotels.
We were sure of what we wanted to do at the start of the trip and where we wanted to finish so those were the places where we booked hotels, everything in between we winged it and drove wherever we fancied. We would either decide where we were going a couple days in advance and book ahead with hotels or just turn up on the day to book, we also emailed our Consultant at Trailfinders a couple of times in the trip for him to book our hotels as it was sometimes cheaper to book through them. They were also on hand throughout the trip if we had any questions or issue.
I would definitely recommend popping in to your local Trailfinders and see what price they come up with for what you want.
I am doing a West Coast USA drive as part of my honeymoon. We did months of research on the best itinerary and came up with the following:
Vegas 5 nights; Death Valley 1 night; Yosemite 3 nights; San Fran 3 nights; Monterey 3 nights; Cambria 1 night; Santa Barbara 2 nights; LA 3 nights; Cancun, Mexico 5 nights.
There is much more info on my planning thread (link in my signature). The honeymoon bit is in numerous instalments and starts on page 12, finishing on page 13. We chose not to do Napa Valley but are having a full day in the wine region of Santa Ynez which is close to where we are staying in Santa Barbara, near LA.
We booked it with an agent in the end mostly because accommodation in Yosemite was fully booked for private bookings on the dates we would have been there but the travel company still had rooms available. We did have the option of solely booking the Yosemite accommodation with the travel company but we did the maths and with flights it would have been more to do it ourselves (marginally) and with the travel company your get 24/7 assistance and ATOL protection which was important to us as it is our honeymoon we didn't want anything to go wrong. We still had/have complete flexibility and they followed our bespoke itinerary.
Hey my uncle lives in LA and we did the west coast a few years ago. We flew into vegas, spent three nights there (with a day to Grand Canyon); flew up to San Fran and spent three nights there; three nights in Yosemite; three nights working our way down the pacific coast highway (from memory I think we stayed in monterey, Carmel, and santa barbara) then five nights in LA. I wouldnt recommend staying that long in LA unless you're planning on spending a lot of time at Disney / Universal Studios etc, it was purely for family for us. We then flew home from LA. Def look at arriving and departing at two diff airports through the same airline as i don't think it adds that much on and means your extra flexible.
We did a slightly different trip last year, Seattle, Portland, then driving down the coast to San Fran, staying in various places in Oregon and California. We did three different wine tastings - one by Seattle, one a day trip from Portland and one in Sonoma (from San Fran). It took about 10 days, and we planned it all ourselves, although the Portland and Sonoma trips we booked a driver for. It was great!