Thermarest says the water vapor isn't an issue, since there's no insulation to wet out, and the internal structures are (allegedly) resistant to mold, etc. I believe they do recommend storing it flat with the valve open, to let it air out a bit.

A salesperson at the local outfitter did find something called an Instaflator (http://www.themillair.com/); it was dirt cheap, so I ordered a few.

It's a neat concept: a 6 or 8 foot long tube with a valve on the end (you use a clear poly tube section to adapt it to lock onto the NeoAir valve securely.) You then blow into the open end of the tube, gently, to get it to open up. You then roll it toward the valve, and the long tube holds enough air that one tube of air inflates the 66" NeoAir enough for sleeping (if you prefer a fairly firm inflation, you might need another half a tube of air.)

It only weighs an ounce or so, but the material is that really thin film-like plastic. The first time I used it, I had a rough fingernail that snagged it and left a few pinholes in it, so I can only imagine what deploying across a typical forest campsite might do. The pinholes didn't affect it's performance, but over the course of a week, I could see pinholes becoming large tears as they snagged on twigs, pine cones, etc.

I'm not sure, in 80% summer humidity where I usually camp, that using a pump instead of my mouth really prevents mositure from getting into the pad. Another disadvantage is that it's 6 or 8 feet long, so if it's raining, you'll have to be out in the rain to fill the pad - no way to sit inside the tent and inflate it.

By the way, the NeoAir all season comes with a nylon pump-style stuff sack that works on the same principle. The problem is that there's no backflow preventer on the valve, so when you get the pad about half full, the air flows back out while you reinflate the pump, and you never make any more headway. (I don't know if MSR sells the sack separately, but you could always tell them you lost yours and would like to replace it.)

I've pretty much resigned myself to blowing mine up myself.