Staying with friends relatives?

At the end of this month I'm to Japan with a Japanese friend and we'll be staying with her grandparents for a few weeks. I'm not great at Japanese and was just wondering what I could say to her grandparents when we first meet to tell them how much I appreciate being able to stay with them. I'd like to make a good impression because I dont want to seem rude, especially because I might not be able to hold actual conversations with them very well!!

Any advice on this topic would be greatly appreciated :)

First of all, say to them " My name is ++. Thank you for inviting me for a few weeks to your house".
(Watashi no namae wa ++ desu. Omaneki itadaki arigatougozaimasu. Douzo yoroshiku onegai shimasu).

Take a small gift for the grandparents(chocolate box, cookie box etc). It's a typical and traditional culture to bring a small gift if you are invited to visit someone's private house.

"A few weeks" staying sounds me a bit too long. Is is really alright to stay there? I think a week of stay is enough for me in terms of common sense.

Take your bath/shower after the grandparent had. Be quite at night. Sleep at the same time as them and wake up as them. Ask them what to do your laundry(They might have their own rules).