USA Roadtrip

[Miss-taken]

Me and my boyfriend are planning on a 3 week trip to the USA next September time. We won't be booking for a while so are very much in the preliminary planning stages. The current plan is to fly into LA, hire a car and drive to New York (where we'll fly home from). We plan to visit LA, San Francisco, Vegas, Grand Canyon, Texas (don't know where yet), New Orleans, New York and possibly somewhere else inbetween New Orleans and New York.
Has anyone done a similar coast to coast trip and have any advice? It's about 4500 miles but we both love driving although I'm beginning to think 21 days won't be enough!!
TIA

[noway2]

I've been doing a road trip across the USA on google street view for the last 3 months,Im going from LA to NY.Im only in texes now, As I keep going off the main roads,and having a nosy around.

Anyway at the rate I'm going it will 2020 by the time I reach NY.

[jno]

I don't think it will be enough either. It's perfectly possible - the roads are good and petrol is cheap - but you wouldn't really be stopping to enjoy it very much. I once spent 3 weeks driving around the north-east, up to Maine, across to Niagara and down to West Virginia and Maryland; but if you look at it on the map, it's really only one small corner. If you actually want to see things, I'd double the time or halve the trip, as Zacsmaster suggests.