She's an experienced day hiker though right? Or is the four day backpacking trip her first trip out in the woods? If this is her first trip other than an hour or two in local parks, her eyes are just one issue.
On Contacts, I'd start with the hand sanitizer & then do a very good job of washing that off. My personal preference would be to use soap & water when possible. Everyone tends to be different but as someone who sweats going up a small hill on the golf course four days of glasses would be brutal for fogging & dripping. If the route isn't too hilly & you are carrying everything (She does not & maynot sweat), then glasses aren't bad & are easy. If she's carrying a full pack for the first time.....
What's your destination & route? Many of the well traveled trails shouldn't pose a problem with sticks & branches. I've never had an issue. If bushwhacking (if memory serves correctly MacNaughton is a bushwhack - it's not an offical ADK 46er & I have no plans to go so if there is a trail, mea culpa now) glasses or even goggles are not a bad idea. I do like wearing sunglasses a lot but on a dozen or so herd paths, I've maybe had the glasses knocked off once or twice.
If in the Whites & your route passes a hut each day, they have running water. How are you washing your hands for four days? I guess you could get by with just sanitizer & still follow proper food preparation guidelines. In order to take them out, she'll need clean hands without alcohol (residue) on her fingers, probably a small mirror too. (I can take mine out w/out but not in) If you're boiling water or purifying, she just needs soap, a small case & small bottle of solution.
How are her eyes? I'm able to go several days without taking mine out, (I'm supposed to & I wear them 3-5X longer but my eyes don't produce that much build up, my wife goes through them 2x as fast & is often losing on & she gets a lot of build up.
She probably should have a back up & then a back up to the back up. Bring a spare pair - (daily's sounds like a plan if she can get them) & bring glasses. Back in 1996 I stayed at JBL & forgot my glasses, once I took out my lenses, I missed a cloudless night (well I saw it was dark
) I was blind to a great night sky.