I can't say enough good things about Mount Princeton Hot Springs Resort (Segment 13). I recently hiked most of the Collegiate Loop and picked up a supply box there. They recharged my electronics at the front desk while I took advantage of a reasonably-priced day pass to take a much-needed shower. The day pass also gave me some pool privileges. I grabbed a snack at the country store, eating it on a patio area at the back of the store, and then headed over to unpack my box and repack my backpack in the lobby area. I had not planned on staying the night, but just a few minutes after leaving the resort, a thunderstorm popped up. So I scrambled back to the front desk, soaking wet, and stayed the night in a nice, dry, comfortable room. The people were always courteous and I never felt like I was a burden. This is an upper-end resort and they don't have to accommodate stinky hikers, but they do, with kindness and grace.
Likewise, the people at Monarch Crest Souvenir Shop (Collegiate West Segment 5), the only other resupply spot right on the loop, were helpful and courteous. Like MPHS, there's not much for sale for hikers beyond snacks--it is a gift shop, after all--but they have an area set aside for hikers to repack and charge electronics, and a hiker box to donate to/take from if needed. I camped behind the sand building next to the tramway, and the next morning I hung out for a few hours in the shop's food area, waiting out some rainy weather. Again, I never felt like a burden.
Kudos to both of these establishments and their staff!