Recomendations for a rookie

[Wwiper]

Hi Forum

Greetings from Denmark... ;D

Planning a roadtrip (first one ever) with my 2 children (23 and 20 and maybe they partners) - so 3 maybe 5 people - we have 21 days. Any feedback would be appreciated..

One of my children would like to see the "Walk of fame" (and Beverly Hills) - Hollywood, Universal studio and Disneyland are also on the list...and then New York...so the initial idea was to start in Los Angeles and maybe use 2-4 days there and then drive of to NYC where 2-3 days should be for shopping.

Visiting Las Vegas along the way and (all) other attractions on the way to NYC.. (so many to choose from)... :D

I would also like to see San Francisco and San Diego, but maybe that's should be the next trip... :D

Is it doable within 21 days?

Can someone give me some pointers, so we can have the best trip ever?

Is't possible to get a Motel/Hotel room for 5 people? - or do I need to plan for 2 rooms?