I want to go to my friend's cottage but..?

So one of my best friends has a cottage he goes to every summer, and I really want to go with him for like a week or so. I feel like he wouldn't mind if I came along, and I would really like it. The only problem is I have a feeling he's never going to ask me to come, because I've never really shown any interest in his cottage. I can't really just invite myself over, so does anyone have any suggestions about what to do?