I'm using the following chord progression and i want to create sort of a relaxing carefree atmosphere similar to the one at the end of planet caravan by Sabbath. I don't know scales very well but i am trying to learn about them and any advice for the sort of moods they evoke would be nice. I've been playing for 5 years but I'm just now learning theory in a more serious level.

F5 with the seventh
C5 with seventh
Then A sus2
Then D sus2

I want to keep it more relaxing than spooky sounding, since it is a pleasant sounding progression... But any advice would be appreciated.

Listen more bluesy stuff, base your solo on pentatonic (minor, for instance). Since the chords you mention don't have 3rds, you can do almost anything without sounding terribly off.