Do you just want to walk the floor, i.e. go see all the guns? Or, do you have any seminars, symposiums, etc in mind?
I think you can hit the floor in just one day (you will be pushing it). Come early and bring comfy shoes and spare socks. You will want to bring a messenger bag or the like for all the catalogues you get and a water bottle.
I would string it out over 2 days just to savor it. I mean NRA has not been here since 1979 IIRC.
You can easily spend two days there. I guess you can walk it and see it all in a day. It is so enjoyable that I spend two days. Really good people and a great pleasure to be around like thinking individuals. Lots to see and handle. There are things to purchase, mostly accessories. All the give aways are history really. You can still find a few, but not like years ago.
It is a lot of fun.
Unfortunately my request off for a day to go to the show was approved and then cancelled so I only have Friday afternoon, possibly Saturday morning to attend. But I'm only worried about the exhibit hall. Taking a messenger bag is a fantastic idea