I just matched in ortho this year, and I don't know what it's worth, but I personally think this is a very good idea. I had the opportunity to do one of these "mini-aways" at a program where I knew one of the residents, so he was able to set it up from the inside, which made the process infinitely more easy. And I think it made it possible for me to get a little more out of it, because I wasn't just another rotater, but someone who they knew was using vacation time to see their program. Additionally, I thought it gave me great perspective on the program and the area.
I would not, however, try and use an ortho block and try to do two programs in one month instead of a normal away rotation; I think that could give the impression that you thought you could beat the system or something, and would not help you in the eyes of that/those program(s). I hope you can understand the distinction I'm making here.
That being said, I'm still a bit of an outsider, so I don't know exactly what it looks like to a program. Just my thoughts. Hope this helps, and good luck!