I've been day hiking / walking with a cinch sack. It's refreshingly simple.
https://www.bookstores.umn.edu/viewP...3#.WegKxRNSxE4
and you should be able to find one for free...
They are quite decent for carrying power and surprisngly not bad on comfort given the use of cord instead of straps. However, I've found the cheap/free ones to be poor in durability ... like, a handful of uses, then they fall apart. There are ones of apparently higher quality you can buy for about $20 or so.