Kit me out for a long trip please!

[StillMedusa]

I'm travelling the USA with my DD2 for two months (September and October) Visiting quite a few States... NY, several southern/mid states, Hawaii and Canada. It's my 'I'm turning 50' md life crisis trip!
I live in jeans as they are practical for my job (which I am going back to ) and don't own a dress.
20kg max luggage
I have no idea what to take other than my beloved Skechers and some flip flops. Not doing any heavy hiking.
Some places will be hot. Canadian mountains in October I am guessing will be chilly.
What do I need? We are staying with friends some of the time, and hotels at other times.
Any advice appreciated!

America is very casual so I'd go for some layers. I'd buy some long sleeve t shirts and wear short sleeve t shirts on top so those will cover hot and colder climates. Jeans fine for Canada.

Mostly it will depend on how long in each place such as Hawaii? That's just shirts and t shirts so could you buy and chuck? Can you list your itninery?

We are starting in NY,. then down to Dallas, then Oklahoma (few days in each place as staying with friends) then to my sister in Denver, then Las Vegas and flying over the Grand Canyon. Then LA for a few days, a week in Hawaii, a week in San Francisco, up to Calgary and Banff mountains for a few days, Toronto, Niagara, then drive to Ohio, then drive to the Poconos mountains near Philadelphia..then NY and home?! Trust me organising this is doing my head in! I should be able to wash stuff at friends' houses I hope.
I think Banff will be cold..but I guess I could buy clothes as I go if I need to, tho my budget is tight.and pack a lightweight puffer jacket as that won't take much space. Would jeans be sensible, or too heavy? I'll take a couple of pairs of shorts and 5 t shirts and a weeks worth of underwear, but just have no clue how much is essential!

Invest in a light shawl. It will be good enough to wear around your shoulders whilst travelling and just going out and about.

Check out Uniqlo for their down gilets/jackets/coats - so lightweight & warm, great for travelling.