Lake Como to Blanca Peak

[Ghop]

Myself and some trailmen ( think scouts ) are taking the Lake Como Approach, camping at Lake Como and summiting Blanca Peak next week. What I'm looking for is the latest situation report. From looking at satellite photos the trees won't be great for a bear bag. True? And while bears are a thing, since we're at the tree line from my research the bigger concern is marmots and mice. Thus, I planned to put a dry bag inside a steel mesh bag and that be hung as a bear bag using the PCT method. We need to guard against the critters overnight ( food trash from supper, hygiene stuff, sweaty clothes, food for the next day ) and then when we leave camp the next morning ( same stuff but we're all gone now ). No one has a ursack or bear cannister and I'm hoping someone can tell me if I'm being overly concerned with this or that the plan is horrible.

Also, with as dry as it is this year, is the water supply at Blue Lakes and Crater Lake fine? I assume Lake Como will be as it's larger but was thinking about filling up on the way up ( for the summit ) at one of the others.

Thanks in advance!