Do they work in those types of machines (I imagine so, but have never tried them.) I go to the sample section of Target, and bring a couple of sample sized pouches of laundry detergent. Very easy to pack.
We go in the summer very year, usually July.
If you pack sample sized pouches of detergent, make sure you put them in a ziplock bag, otherwise you might be doing laundry on your first day

.
I recently found sample boxes of dry detergent at Target so I would recommend those as opposed to the liquid pouches (and don't forget the dryer sheets). You will definitely need to Change clothes more frequently.
Band aid sells a small chafing stick which really help to keep blisters off.
Try to keep long hair up. It really helps.
Water, water and more water in case you didn't get that yet. LMAO! Freezing them is great.
We always being one of the hand towels from our room to towel off on hot days.
Wear shoes which allow as much airflow as your personal preference allows. I was never a fan of flip flops for walking until I was forced to wear my Reef Fannings one bad weather week (everything else was already wet and I had packed these for the pool). After one day of wear, I was hooked and haven't gone back. My feet were cool and comfortable and I didn't have to worry about wet shoes.
Make sure you sunscreen your feet and ears!