Since I got the firmware update for my YT-1200 the other day (and I had to pull it apart anyway), I did a slight re-vamp of the GoBox for my FT-991. It's a 3U box from MCM with the FT-991 Mobile Bracket and YT-1200 mounted to a rack shelf. It's truly a "shack in box" with an MFJ-1708 transmit/receive switch and SDRPlay and everything I need to operate portable, I can just plug in AC or battery, an antenna and be up and running. It's plenty heavy so it's not a backpacking setup, but for car camping and field day it works great.
I changed out the battery connectors for Anderson Powerpoles, redid the ground wiring with solid-core wire, mounted the line isolators and mounted the SDRPlay. I also added powerpoles for a quick disconnect for the Midland Speaker since it is too bid to fit with the covers on. I also added a USB charging port. I have a small padded Pelican (type) case for the headphones, speaker, and logbook.