Hey there!  I think her going over to your boyfriends house would be the better option, especially if you’re concerned that she wont be comfortable in a completely different environment and worried that she wont get the attention she needs with someone only giving her attention twice a day. I would just say that you make sure he knows all the care she’ll need and what to watch out for in case she gets sick or anything like that. Good luck! 

Agreed, leaving her with your boyfriend is by far the best option, seeing that she knows him and his cats and has been there previously.

Agreed as well. The only ones I could trust the most were family members. They have pets and they actually cared about how I wanted them to take care of her. They weren’t perfect, because I can be very specific and detailed in my expectations. But she had an environment of consistent interaction with appropriate care and attention. It sounds like your plan is the best option. She has been there before, he will be there a lot to spend time with her, he has handled her before, you are taking her familiar environment with her (cage, setup, etc.) It sounds most ideal.