I've heard of farmers drying in their barns.
Bugs might be an issue.
I don't think dryness kills or harms THC. It's hydrophobic, and a lipid. You could have it completely dry and it'll just be a powder, every bit as potent. Freezing it will cause fractures on the lipids, and will degrade THC.
The reason a small amount of moisture is desired is for a smoother, less harsh smoke. I'd take harsh dry smoke over moldy smoke any day!