Hi Julie
Thanks for your message.
Clothing wise you'll need a variety as the temperature does vary throughout the country even in October! A mixed of t-shirt and shorts and warm jumpers and trousers. There will be occasions when you may want to dress up a bit for dinner but there is no expectation to dress formally.
WIth regards to money, card is accepted in most hotels but cash is the preference in a lot of places, especially on trains and other transportation. Most hotels will have ATMs so you will be able to get cash out whilst in the country as well.
I hope this helps! If you have any further questions let us know.
Best wishes
Just You Team