Lauren,
When we stay at a hotel without a kitchen, this is how we do the milk/cleaning thing;
We buy a styrofoam cooler (just a few bucks at the grocery store) and keep it stocked with milk and ice. We replenish the ice twice a day. I buy milk in half gallon jugs (depending on the length of stay, I buy more or less jugs) because the half gallons are easier to cover in the ice in the cooler.
I also pack a bottle of dishwashing liquid (like Dawn) and wash the bottles (sippy cups in our case) in the bathroom sink. Hotels generally have their water set to a very high temp, so getting very hot water is usually not a problem. Put a drop of soap in the bottle, put the bottle nipple IN the bottle, fill the bottle half way with VERY hot water, cover the top with a folded face cloth and shake, shake, shake hard for about 30 seconds. Rinse, repeat. Make sure you rinse the bottle/nipple VERY well with really hot water to make sure you get all the soap out. You might find a bottle brush (can buy them at target in the baby section) useful, although I don't generally use them. You can lkeave your bottles and nipples to dry on a clean hand towel on the bathroom sink. At the age of one, you don't need to worry about the bottle bing 100% sterile like with a newborn, but this method will definately get your bottles and nipples super clean.
In regards tot he need to pack on the pounds. <grin> We had this same issue when my DD was at that age. My Pediatrician recommended carnation instant breakfast. It will add calories and vitimins and minerals to your baby's milk.
Hope this helps. Have a fun vacation!