Encumbrance has been disabled, so don't worry about how much loot you can carry. Be more concerned that if you die with your backpack completely loaded up, you risk the chance of not being able to make it back to it before it disappears. In the past i've carried a bedroll and placed it in my toolbar. If things get harry i tend to drop it so if i do get wrecked i can spawn closer to my latest backpack. Doing this means your original base may have z's in it upon your return...
There was a post in this thread not too long ago that talked about adjusting the length of time your backpack remains. It definitely isn't long enough for you to make the trip. The post also gives instructions on what change to make to have it remain in the world for longer. You can follow that to help. In the future, craft or find a box, and dump all your loot in that. Mark it on the map, and you'll be good to go.