From the well-organized Master Drill Sergeant who worries about what to worry about next (me
1. If you weren't bringing the new horse home this weekend, I would say leave Harley parked right where he is, until after the show.
2. To really overthink this, If the mare is coming this weekend, which is worse?
Bringing her home to be by herself for a week or bringing Harley home, then loading him up for a show in a week? How will the mare handle just being moved, meeting her new friend, then having him ripped away (she doesn't know it's only for a few hours) and she may spaz out.
You will be at the show and will have no way of knowing if she gets tangled up in something.
3. What you're going to have to be really cautious about, is both horses becoming so buddy sour that one of them may get hurt anyway, when the other one leaves.
With your daughter's show season starting, you aren't going to always be able to take both horses together.
That is how I ended up with three then four horses
If I were to load Joker to take him somewhere, Rusty would have a meltdown.
If I were to load Rusty to take him somewhere, Joker would say "GREAT! More grass for me!" and keep right on eating.
4. In a perfect situation, it would be nice to take the mare to Harley's boarding barn until after the show and bring them home together.
However, given how Harley gets pushed around that isn't a good idea unless the mare could be separated from the rest of the herd.
You come across as also being very well organized so a little chaos isn't going to upset your horse apple cart and have you reaching for Xanax, regardless which direction you go. lollol
With two horses and leaving one behind, it's never easy to know the right thing to do. Which, not to beat a dead horse, is how I ended up with three then four