Miami to San Francisco - late Sept to late Oct

Hi Roadtrippers,
My cousin and her boyfriend are arriving in Miami late September and planning on driving from there to San Francisco. They are planning a couple of days with family in La and taking the coast road to San Fran, probably taking a couple of days to do this. All together they probably have 24 days between Miami and LA. They'll definately be on a tight budget. They're mid-20's so any advice on hostels would be good, plus probably good motels.

They've asked for some tips for places to go. They'd be looking for great scenery and as much of a taste of american culture as they can get in that time. I've roadtripped there quite a bit but haven't been to Florida, so that's a bit sketchy for me, but imagine they may want to do the Universal / Disney thing. I was thinking of not sending them too far north as I think they will definately be wanting to take in the Grand Canyon, Navajo and Monument Valley. I'm pretty sure they'll want to have a day or two in Vegas and I loved Yosemite so will be recommending it. So I'm thinking of getting them west as quickly as possible so they can spend the time there - but maybe you can advise of places or routes that I don't know of or maybe you would recommend goin a little further north?

I was also going to recommend New Orleans as I thought it was a really unique place.

Also was thinking of sending them up PCH from San Diego so that would be the west coast target.

Any ideas will be gratefully received.
Thanks.

The reality is that there are millions of places you could stop on a trip that goes from coast to coast, and trying to narrow them down is a fairly impossible task, and its even more difficult when you are trying to offer suggestions for a 3rd party with the only real guideline as "a taste of american culture" (which really is everywhere.)

What I would advise is that they start doing some more research, and plan their trip, rather than just going where you or anyone else "sends them." Following someone elses plans really isn't much of a roadtrip in my book, even if it involves thousands of miles of driving!

Rather than offer lists of stops, I'd tell them to pick up some books, look at other resources like RTA's Map Center and list of attractions, and then ask for tips and suggestions once they know what they want.