i used the nrs soft cooler for a time when i first got into rafting. nice design with solid strap down points but it didn't take long for it to leak though. not a problem on the river but would soak a car seat after abit. held ice for a couple days though.
my "solution" was just switching to all hard shell coolers after that and wondered why i didn't go that way in the first place. a small, basic white igloo or whatever and be done with it is my advice.
edit: it does look like NRS changed the liner material to urethane so might hold up better now. i really doubt i was the only one with a leaking problem with the older design.