I would just keep giving them a LOT of separate-rooms time, so that the older cat feels like she has control. Kittens can be really annoying to older cats; the older one can even end up sleep-deprived. (For some reason, kittens never seem to need to sleep!) I'd worry less about them getting along right now, and just keep each of them comfortable in their own space. And I wouldn't go out for the day and leave them in the same room.
I've known several cases where owners bring home a puppy or kitten and the older animal can't stand them, but then they become pals when the baby gets older and calms down.
Also what about getting a small cat cage so the kitten can be in the room with you and your husband along with Kaylee, without the kitten pouncing on her constantly. Just put a lot of toys in it. Maybe it will help them learn to be in the same room without fighting? They can play with their paws through the cage if they want to.
I've known several cases where owners bring home a puppy or kitten and the older animal can't stand them, but then they become pals when the baby gets older and calms down.
Also what about getting a small cat cage so the kitten can be in the room with you and your husband along with Kaylee, without the kitten pouncing on her constantly. Just put a lot of toys in it. Maybe it will help them learn to be in the same room without fighting? They can play with their paws through the cage if they want to.