Hey Wunderin'...sounds very Dharma Bums to me (check out the book if you haven't)
Not sure about camping on beaches in the US actually. Legal? Safe? I did it in Borneo last year, but no idea about doing it in my own country!
I'm carrying a 50L pack -- but nowhere near full -- for my big trip. I left home with it at around 12 KG, but a lot of that is work crap like camera and laptop goodies.
Tents are indeed heavy. Something to check into for camping vagabonding -- I've met several people just carrying a lightweight tarp that can be rigged into different kinds of shelter. They have 550 cord and some light stakes. Some also had hammocks to get off the ground, then run a cord between the trees above you, drape the tarp, then stake down the corners. Presto...a hovering tent.