As far as I know, fastcamo isn't the only drawback, it's just the most noticeable and annoying. Right?

The problem is, I don't know how much time is okay. If having 75% wilderness time is okay, then fine. But if it needs 95%, I'm going to be in trouble.

Also, does being an explorer help? The help file says this expertise allows for time spent in civilization, but does it only mitigate some negative effects or does it lower the minimum wilderness time needed for fastcamo?