Re-foster or no? What is best for the dog given I may have to return her?

I fostered a timid shelter dog about 1.5yo for 3-4 weeks. She came to me underweight, terrified, unfixed, coughing, and with some house-training issues. We made a lot of progress, good weight gain, spayed, absolutely delighted to meet new human friends, figuring out other human rules. Then, I had work shit happen and had to leave her crated to 9-10 hours, and it just wasn't fair. Even when I was home, I had to crate her or be constantly interacting with her (crate if I go to the bathroom, wash dishes, etc.) I thought it was best to return her. She cried, I cried, it was awful.

Whelp, I made the mistake of going back to the shelter and while she's still at a healthy weight, she seems more reactive and less likely to get a good home while stressed. I would love to foster her again, or do a shelter-day break, but I know I have to travel again soon, and again in the summer. My question is, would it be harmful for her to do a single-day or short-term break? The sad thing is, I really think this dog would be great for a rough-and-tumble kinda 10yo kid, and I just wanna help her find that kid. (DC, Northern Virginia area if anyone is interested)