I would add Sugar Magnolia and Box of Rain, also from American Beauty. All are great songs on one of the best albums of 1970.
Those are popular songs, and Box of Rain is poignant when one considers Phil Lesh's father passing away inspired the song. I always appreciated their live performances much more than the studio albums, not even close in my ears.
Consider Grateful Dead Live at Fillmore East on 1970-02-11
The Not Fade Away is unlike any I've ever heard. The Dark Star, Spanish Jam, Turn On Your Lovelight is a an almost one hour jam that had Peter Green (Fleetwood Mac) and Duane Allman plug in to jame with the Dead, not to mention other great musicians from their bands and Love. Of course the famous shows of two and three nights later are available for listening on the UCSC Archive and epitomize the sound of 1970 ala the Grateful Dead much more, and better, than any of their studio albums.