I recommend that you install Linux on the laptop alone! Linux will work on that hdd, but will be slower. If you can, buy an used ssd for it. 256 GB should be enough for a lot. That 1 TB hdd could serve you as a backup disk.
I also recommend to overhaul your laptop. Remove the dust with compressed air and reolace thermal paste (should be done every 2-3 years anyway).
It boots faster and is slightly more responsive as the link suggests. Neofetch has different logo.
It doesn't have the driver manager so LMDE doesn't play well with Nvidia gpus.