Tips for an Americas West Coast Trip

Hi there!

Planning on spending Protected content at the beginning of Protected content my dream of seeing South America. I plan to start in the US to round the whole trip off, the route would be: San Francisco -LA-Palm Springs-San Diego (USA total about 20 days)- Costa Rica visit both coasts- Equador-Peru-Chile-Argentina-Uruguay-Brasil.

Some of the legs would be overland, some by plane and a bit ferry/ boat if possible (like Buenos Aires to Montevideo). Do you have any tips about local travel and accomodation? Right now I'm thinking of going to STA travel for some kind of (flexible?) flights package and organise the overland travel locally and use Air BnB for accomodation- but there must be also local services and smaller airlines that shuttle between the South American Countries? I'd like some flexibility and to avoid the typical backpacker thing (I also feel too old and umm "seasoned" for that, haha) I know in some places like Cusco or Salar de Uyuni I'd be just part of the huge touri crowd, but still want to experience and mingle with local culture and traditions, eat locally and maybe even stay a bit longer in places.
Any ideas welcome, very excited about what insights you guys have for me!
Hannah