I'm almost sure she won't act up a bit. Even if she is too hot from whatever Bob's been feeding her, that horse is as broke as they come. She was before Tiff had her, and she stayed steady through everything Tiff did.
ecurbh's first trail ride, when he'd only been on a horse a few times, was on Kat.
She has a few issues to be worked around... she has a tendency to get herself caught up in ties and she'll pull till something breaks if she gets hung up. Even getting her head under the lead rope will set her off. She needs to be tied high and short, always, no exceptions. I want to make sure Bob's clear on that.
And she's real paranoid about strong male horses around her rear end. She hates Bay, if I got any closer to ecurbh in the picture above, she'd turn ass and nail him. Bay knows it, that's why he's turned away, and I'm trying to get him to sidle over close enough for a picture. That's as close as I could get.
So she needs to be given space, isn't fond of close quarters with strange horses. I hear she's bonding just fine with Bob's two geldings, so she'll likely be fine with Bob getting close if needed.