You are exactly correct about the laptop, its SATA 2, so any SSD is faster than it needs.
I am really happy with Mint so far. I switched to using libreoffice a few years ago on win 7, and that made the final transition to Mint very easy.
Next task - business card scanning and software with functionality similar to CardScan. With 6 K business card scans, I can't just leave that behind, and really still need business card scanning capability. That one is actually still on my xp box. I guess in theory, I could try to run it under wine.