jwr,

If your going to use wood use salt treated lumber. However it will stink for about a year. Forget the nails! - use screws to attach rungs and any x braces. I use "Tap N Seal" 10 x 2 post frame screws. Screw has a head flange and rubber seal - perfect for this kind of project! I stick screw into a carpenters wax before tapping into wood. This makes going in alot easier and prevents squeaks. Every couple years you need to tighten screws a bit but if properly built will last for years and years.

Having said all that, I've seen many guys put together some crappy wooden stands on real nice hunting farms. Then they tell you to go ahead and hunt that stand. Not Me - I would rather stay home with all my bones,head and spine in one piece than climb into a wooden ladder stand that was thrown together or neglected.