"but it is only 64 Gb"

the thinkpad 8 should use an mSATA ssd so you could upgrade to 128GB (+) and fit it all on the main drive.
You can clone the existing 64 to the 128 then copy/install the band in a box files and realtracks/drums to it - this way you won't have a usb hard drive hanging from it using power.
You can put the old 64 mSATA in a usb 3.0 enclosure or keep it as an OS backup.