Done a test computer to go through the motions and I think I have averted a Win 10 forced upgrade.

Linux Mint install, ( wipe out all old stuff, xp etc re-format drive).

Internet: Telstra USB stick.

This means, a laptop at least can be portable.

Much is DIY,

Can be done in less than 1 hour once one gets hang of it,
( not including time spend to research )