Amphenol makes some nice panel mount USB connectors (MUSBD11130) that are easy to mount to a case. They are also sealed. The connectors solder to the PCB for an adequate mechanical setup. FTDI makes single channel USB to UART chips that don't need an external crystal or voltage regulator, just a few passive components. One of the 0.100 screw terminal strips provides a simple connection for wiring to. The resulting board is small and easy to put in a project.