Why do you feel you'd need to get work done specific to a curriculum? Sounds as though this might be the ideal time for some "unschooling" - e.g., decide that until next Spring (say) you're going to do fun things with her, and of course they'll involve learning because 5yos are learning machines, but you could afford the time to let her "drive" and develop her own instincts. Given how bright she is, from Spring to Summer would surely be enough time to make sure she'd covered what's expected of K, if you wanted to.
My only reservation on this is that you said she was keen on going to her brother's school - it would be a pity if she felt that you'd deprived her of doing that. When do you have to decide? Can you prepare the ground a bit and then ask her what she'd prefer, making clear that you like the idea of homeschooling next year because it would give you plenty of time with just her to enjoy helping her learn whatever she wanted to?
