Rigging a Backpack - How would you?

Rigging
#1

So Im working on a character that has a backpack. Ideally I would like to be able to animate the pack to add more bounce and what not. Though, Im struggling to plan how to do it. I’ve considered an IK chain so the straps will follow the pack nicely, but, if I move the pack down or out from the body, the chain appears to go through the shoulder. Would it be easier to just try and do what I can with weights, making the top of the strap weight to the clavicle?

Is there a technique for this that I`m not thinking of? It’s definitely possible. Still a beginner.

#2

although IKs seem tempting in this case because they would make sure you get no / less stretching on the straps you would probably make your life way easier with some free floating joints, simple fk setup or ribbon style rigs and let the animator handle how much what part stretches.

#3

How about using clusters/lattice?