Im gonna try to make it next spring. Got too much going on lately to make the trip. But yes, its is a huge show. Bring some GOOD walking shoes! It will take a good 8 hours just to walk through it(going up one aisle and down the next) one time. Also, bring a notebook and pen to write down if you see something you want to come back to and look at later. You WILL forget where it was! Dont buy any ammo or anything heavy until the end of the day unless you want to walk a few miles carrying that stuff. That should about cover it, but Im sure others will chime in and give a few pointers.
Forget about going back for something. Best buy it when you see it. I have tried going back. First it was hard to find. Second it was gone by the time I got back to it. Carry a backpack or something to stuff small items you buy in. As I buy rifles I will carry some spare slings in mine. It will make it easier to carry them if I find some to buy.