My biggest concern would be whether you can get all the necessary drivers to support XP via bootcamp on that machine. Even on a 2010 MacBook Air (where apple first discontinued XP support) it was never really possible to nail everything down 100 pcnt and I suspect a 2012 era machine is going to be even more awkward..
Personally I'd give the 30 day trial of VMWare or Parallels a try and install XP as a virtual machine, as it might be sufficient for what you need
We run USB to serial adapters on XP VMs under Paralels on a daily basis without any issues (though the sort of stuff we're doing diagnostics/reprogramming/monitoring of never needs serial connections over 57600 bps).
Only virtualization software I'd steer clear of from the outset on this would be Virtual Box - Ive never seen it play as nicely when it comes to setting up/using USB serial adapters as the other two, and I'd reckon that's the critical part of your particular XP setup.
Oh and one more thing if you're taking a macbook near mechanical stuff, I'd try to get something to cover the magport when running off battery - you'ld be amazed the amounts of bits of metal swarf etc that can find its way into there and get stuck like a limpet round the port. We didn't and have lovely scratches around the mag ports from regularly trying to pick it back out lol
something like this (though only the magport one is required)
http://www.ebay.co.uk/itm/Anti-dust-Silicone-Port-Plugs-Rubber-Cover-Set-for-Retina-Macbook-Pro-11-13-15-/371099679120?pt=UK_Computing_Other_Computing_Networking&hash=item566743b990