This can turn a 150-250 calorie an hour walk to a 300 - 600 calorie an hour walk while you're walking the same speed / socializing. It's definitely uncomfortable but doesn't interfere with socializing and thinking IMO (and of course, I'd start with 10 lbs first)
You can use sand or dumbbells but I did it often enough that I got a generic ruck plate and a high quality rucking backpack (GoRuck isn't cheap but I like their quality and the fact that they're made in America).