I have a studio apt in town, and own a nice home a few hours away. I only get to go there infequently these days. My daughter needed a place to stay for a month or so between apts. She is in her 20's. My studio is TIE-NEEE!. She slept on the coach, about 3 ft from my bed. Additionally, there is someone in my life, and he occasionally stays with me in the apt. Before she moved in for the month, we talked out the details and worked it out regarding privacy, etc. She had one or two other places to crash with friends, and she had a little more space there. So weekends and occasional weeknights were away. Plus I was away at times as well.
She moved into her new apt. and is happy. She brought her new b/f to my apt, and also some other friends and we made dinner before she moved. It was a very memorable time for me. Granted, it was a short time, and if it had been longer, it would have been more complicated. But the important thing was talking up front which has been addressed here several times.
Although you're an adult, you have to remember that your dad will have some basic house rules. I certainly still do. However, if I know that we can trust each other to do our best to make nice, comfortable, safe, etc. then I will accomodate a lot. If you do your part, I'll be your dad will do his to help you feel comfortable.
Best to you.