Since it's family, go Tailscale (mesh network).

There's a couple ways to use it:

You can run the client on every machine, so they're all members of your mesh net. Easily access any of them from anywhere, at any time, using whatever remote utility you choose: VNC, RDP, Dameware, etc. You can easily map drives too, since your on the same LAN. (Just turn off MagicDNS - it can interfere with local name resolution).

You can run it on a single device in each location, enabling Subnet Routing, and that device will route traffic into the LAN on which it resides. I use a Raspberry Pi W Zero for this, and it works fine. I can print, configure my NAS, cable modem router, from anywhere. Q

I run the TS client on anything that can, Disable MagicDNS, set the TS network metric to 5000 (this pushes it's routing priority way down, preventing accidental routes over TS when I'm home), and enable it to run as a service.

Worst case, if someone doesn't want to run the client, you can setup Reverse VNC using your Tailscale network with the Funnel option enabled. This Funnels traffic into your network via an internet-exposed interface hosted by Tailscale (you can also host it yourself on a VPS).