William Least Heat Moon While not strictly a "hippie" book it is a deeply philosophical journey into the rural heart of America by a native american, an absolute must read I neglected to put a link oops Blue Highways by William Least Heat-Moon (goodreads.com)
I need to read this. During Lockdown, people have been reading this one and "following along" with Google Earth. I heard the two sequels were also very good.
if you do indeed decide to read it and enjoy it, his mentor Black Elk has an amazing read Black Elk Speaks by Black Elk (goodreads.com)