As I was planning the trip, I decided to take along my UHF only mobile radio, to see if I could have any luck there, and I was pretty sure it would fit in my carry-on. That quickly turned into me realizing that if I could take that radio, I could just take my 857d and have a proper HF activation. I checked the TSA website, and ham radio equipment is specifically listed as "allowed" so I figured I shouldn't have any problems (and I didn't! They didn't even bat an eye at airport security!)
With that thought in mind, into the carry-on went my 857d, some power wire, some coax, and my antenna analyzer. The buddiepole kit was my personal item, so I managed to pack 4 days worth of clothes, and an entire 100 watt HF station, without needing to check a single bag!
On the day of the activation, I got power for the rig using a power cable I had made up months ago that had battery clips on one end, and power poles on the other end. This way I could just clamp onto the battery of whatever rental car I was going to end up in, and use that for power. The rental ended up being a Chevy Cruze, which worked out just fine for getting me and my stuff around town.
As part of my work, I had shipped some equipment ahead of myself to the first office I was at, and then threw it in the car to take with me on the drive to the second office. This equipment totaled just under 70lbs, and is all in a Pelican case, which turned out to be the perfect anchor!