I just returned from a trip with a 20 month old.
Neither of my kids drank milk, so I didn't have that problem. We packed take and toss sippies and just used water/apple juice.
While my 20 month old naps at home for up to 2ish hours (daycare has a set naptime, so I think the most she can nap in a day is 2.5 hours), she RARELY napped in the past week. Maybe a quick stroller nap here or there but nothing like her epic naps in the real world. And shockingly she slept through the night most nights whereas at home she wakes pretty regularly, her older sister can sleep through anything but a leaf makes a noise in the woods and this one is usually awake. She slept through the boat horns from the Poly every night.
Her normal bedtime is around 6/630 but she was up until 830 most nights and I can't remember the last time her diaper leaked (she did have a slight blowout while there, i just threw the pants away)