Look's like your carrying a hell of a lot of kit.
I used to be the same but to be honest half of the kit I used to take was never used.

Just a thought ,did you add pre load onto the rear shock?
if not this can cause the chain to stratch more.

I just returned from a 4000 mile trip and the chain did not need any adjustment.

I have 2 alloy panniers,one carries all my camping kit and spares,the other clothes with some room to spare.
My tent is straped on the rear rack and that's all i need to take.
If It does not fit in the 2 panniers I don't take it.
Traveling light is more fun and there is less chance of things getting nicked off your bike when you pop into a cafe or a shop.

Ride safe and have fun