Well I think you can ask her to meet up at some place and just do bowling for a while and skip the gym haha.

But then when I invite her to do something she flakes more often than not and then a couple days after she asks me to do something together (women ay?). So I'm wondering why is she doing this? She flakes on my dates but asks me to go on a date a couple days after.

She's on the rebound. Typical way of reaction for a girl who's on the rebound. I've been there before, just play it cool... take it easy.

Telling her you were busy was the best thing to do.

Your plan looks solid. I wouldn't make it a "surprise", just mention it at some point during the training like "hey, you know what would be fun? We should go bowling at [place name] after showering" then proceed with another rep or w/e.

You can judge how to bring it back depending on the way she answers. If she makes it sound like she wants to, ask closer to the end of the workout (not at the end, easier to flake saying she's toasted or w/e). If she makes it sound like she doesn't want to, say something right ahead like it might be for another day then. Don't ask again that day as it would sound needy.

If she comes bowling, you have good IOI, do go for a kclose at the bowling place. To prevent LMR, make sure you escalate, don't just dive in to kiss, it will feel natural to her. Idea that comes to mind is tease kino on the way out and as you step outside, grab her by the waist, have her face you and dive in.

Another thing I would try is if you do get kclose, try to bounce to another location (coffee, drinks, dinner, snack), again if she refuses, don't ask again.

Basically, to have her move off the rebound, you have to make her feel comfortable with you. To do so, have her feel like all of this is happening naturally, nothing is forced onto her (reason why she is flaking when you are setting meets but isn't when she is).

Hope this helps.

Cheers!