Internal/External Hard Drive strategy?

I would appreciate some input as to what might be a good hard drive configuration to use to edit video with PPro on our Win 10 notebook computer. We also need to be able to transfer projects to other desktop PCs fairly frequently so portability is highly desirable.

The notebook is currently configured with an internal 1TB 7200 RPM SATA 6Gb/s HD and a Samsung 960 EVO 250GB M.2 drive for the OS. External ports available for possible external HD options include two USB 3.1 Gen 2/Thunderbolt 3 Combo Ports (Type C), two USB 3.0 (USB 3.1 Gen 1) ports, and one USB 2.0 port. From reading posts here it seems that Samsung T3 drives are quite highly regarded. Were we to go with the T3 option, would we benefit from more than one T3 and what would be a good way to configure HD usage within PPro projects (Scratch Disks, Media, etc.).