Hey @NikNik
I hope you have a wonderful holiday! Are you going on your own or accompanied?
It is nearly 20 years since I was in the US but I spent most of my primary school years there, including in Chicago.
SF is my favourite US city by far. Make sure you use the cable cars (trams) as much as possible, they are great fun - especially up and down those hills 🙂
I have been through Hawaii numerous times but never stopped, all I can tell you from that is hot & humid (which may not be now as it is spring there)! It looks beautiful.
I have just one peice of advice about visiting US cities. Wear your intuition on full alert. Even in the middle of the day there are parts of these cities which are not terribly safe, and it doesn't necessarily look all that different - you may just walk up a road on the way somewhere and feel the temperature drop - take a bus or a taxi etc if you notice that. Don't walk. You wouldn't walk around King's Cross in the middle of the night, it's a bit like that kind of unsafe but not necessarily obviously so.
Sorry I don't want to scare you - just be a"lert" 🙂 and take care so you can have an awesome time.
Kindest regards,
Kristin
PS I should also warn you if you like eating healthy food that can be a huge challenge (it was very much so the last couple of times I went). The closest thing to "healthy" was Subway. Even in restaurants and cafes so much was laden with fat, sugar and salt - in huge servings.
Oh and they tend to serve the salad first (if you're lucky enough to have one offered)!
) 
