Some ways to go about doing this:
1. Get a bag of holding.
2. Use the suggestion on the core books to only count weapons and armor. Any else is fairly negligible, usually (unless it is intentionally being abused).
3. Get a cart or wagon. Most of my characters either travel light because they don't like the tediousness of being bogged down (even if the rules say you are unencumbered, 50 pounds of gear is annoying) or when they need a bunch of stuff, they buy a wagon, a couple of oxen (best value for pull capacity), and a horse with saddle bags. You can really start ignoring the light items once you've done this.
4. Compartmentalize. Your character probably carries most items in some kind of container, whether it be a backpack, large sack (my preferred method as it can be dropped as a free action), belt pouches (which in turn all are "contained in" a belt), or anything else. Keep similar items together in a single container. Once you have the container's total weight (including contents), you can just keep track of the containers individually. It's also fairly realistic. An adventurer would want to have similar things together so that they can quickly find or get rid of everything related (for instance, once you've left the mountains behind and your poor swimmer character has to cross a big river, you can drop the climbing gear case).
5. If your DM is OK with it, assume all coinage is converted to platinum (or gold). Adding up the number of coins in 3 pp, 87 gp, 25 sp, and 56 cp can be a pain. But if you instead have 12.006 pp, it's easy to add up 1+2+6 (and lighter, so you can usually just ignore the money altogether).
6. Let the barbarian carry all your stuff. He never needs to keep track of that stuff anyway, since he can carry 200 lbs. before being encumbered.
