I found my load bearing vest to be too cumbersome when trying to crawl. Remember that anything you put on your chest is likely to get smashed when laying prone. Your best bet is a battle belt.
At the weekend battle I played earlier this month, I found that the only things I needed were a radio, pistol, and 2 spare magazines. Everything else I had intended to carry got in the way. You don't want to inhibit your movement in any way.
^^^ ALICE gear is nice and cheap and you can even get ALICE to MOLLE adaptor patches if there are other pouches you want to put on. I actually prefer my ALICE rig to my MOLLE rig for under my ghillie since its smaller and more mobile. However, the only down side to ALICE is that there really arent that many accessories out there for them anymore, and the ones you can find are typically only for 30 rnd AR magazines, so if you run with an AR its great.