1) No treatment. Studies have shown in most backcountry areas of the Western US this is pretty safe, and people are far more likely to bring a pathogen into the backcountry than get infected with a pathogen from the backcountry. I don't like this method for peace-of-mind reasons.
I guess I'm old fashioned and yes I'm just old too. But I really don't use much in the way of filters, treatment and such in my backcountry water consumption. First of all I won't use water from areas that have livestock there. I will only use water from sources that run freely in gravel, rocky stream beds, preferably as close to their source as possible. I am pretty picky about where I camp and what water I use. I don't ever remember being sick that could be attributed to the water I drank. Just my take....
Cowboy Action Shooter; Endowment Life Member-NRA
The Original Rocket Scientist-Retired
"My Father always considered a walk in the mountains as the equivalent of church going."