Could use help to plan a trip from CA to FL

[MelGhara]

Hi everybody!
I am new to the site and to leaving help messages in a forum (so you know).
I am planning a 3 week RV trip from (Los Angeles) CA to (Fort Lauderdale) FL
with my son (renting the RV).
I need to get to FL in 8-9 days, stay there for 6-7 days (visiting relatives) and drive back in 5-6 days (want to drive 3 hours in the morning and 3 hours in the afternoon with overnite stays at campsites).
Being my first extended road trip, I never realized that to plan this successfully and fun, would be so difficult! So please help me ... what route should I take to see the most famous landmarks? (could you list it from CA to FL and perhaps back from FL to CA).
I welcome all suggestions not only on the route, but also on anything else that an experienced "traveller" would suggest.
Thanks in advance, Mel G.