How cold will it be? Do we need to bother w/ jackets and sweatshirts? I've pretty much decided jeans will be fine for excursions and we have dinner clothes. Is there some type of cover so the pools and hot tubs can be used? I lived in Alaska as a very young child but we were way north of where the Wonder will be and I don't remember much anyway. I want to avoid taking a bunch of stuff we don't need, but I absolutely HATE being cold so have to take that into consideration. TIA.