Attila,
I've used my standard Army Issue ALICE pack (Large, OD Green, type 1 each) for the last 20 years and swear by it. That new MOLLE abortion pack starts off at 30 lbs, and the frigging chest strap is 3 feet long (WHO needs a 3 foot chest strap???). The plastic frame breaks in extreme cold. it sucks!!
The only additions I've made are several additional pockets sewn on by General Jacksons (2 claymore, 2 medium, and 2 large). I've had to replace the frame once in 20 years due to a baaaaaad jump (bent the frame all to hell). I also have a LOWE ruck top flap that I use for extra gear when the weather dictates a little heavier load. Plus it holds a M240B in place on an exercise, but that's beside the point (Blitz did mention the 130lb infil ruck).
I've used braided 550 cord for the handle on the ruck and the carabiner for years. makes it handy to hang on a scale to check your weight as well. Buy extra straps whenever you see them. Excess of 100lbs tends to wear out the quick releases, though a flexcuff will solve the issue temporarily.
Keep the waist strap on your ALICE. We used to cut them off back in the day, but it comes in handy when you are skiing with your ALICE. If you don't like the straps, just tape them up out of the way.
I use boflage for painting my gear and guns, (it's a flat semi permanent paint). some of the surplus stores will carry it. the kit usually consists of 3 different colors, and a fake leaf for patterns (sand and OD are the two kits I use religiously), and augment with white paint for winter camo, and some white medical tape. If you use Krylon, make sure you get the FLAT colors and not the shiny.
If you are rucking, start with low weight and distance. 35 - 45lbs dry weight at a nice walking pace once or twice a week will toughen your feet up so you can increase your distance (start with 3 miles, and move up 2-3 miles a week). From experience, running with a ruck will lead to medical issues further down the road for you. Short distance spurts are better than a long jog. I recommend not running with one. but it's your choice if you want to walk when you're in your 60's or not.
Stras sends
De Oppresso Liber