Rachel, you need to go with your gut feeling. If you have a strong feeling that you should go now, then go. I went through this with my aunt last Dec. She had been admitted to a NH in late Oct. because she was falling a lot. It was discovered that she had a sore just below her buttock, which would not heal. By the beginning of Dec., he was unable to talk much. I got a strong feeling that she wouldn't last long. I also thought of maybe waiting until after Christmas, as money is always tight...but the feeling I should go was too strong. So I flew to see her (had to charge it) on Dec. 6th. I saw her that day and she was in bad shape, but recognized me and I was able to tell her how much I loved her and appreciated her. The next day she was comatose and didn't appear to know we were there. The following day, while I was flying home, she died. So I am very glad I listened to my instincts. I took pictures of us together while I was there, too.
This does not mean that your dad's death is imminent. However, if you strongly feel you should go, then do it. In my case, I obviously didn't return for her funeral, but I would rather have seen her while she was still alive.
I am glad you are going to see your dad. Our thoughts will be with you.