I'm not in a fixed location
In that case I'd choose a different solution than running a few node. Basically anything designed for mobile will be much easier to use.
The HDD is really just to support an up to date blockchain, and maybe half a Bitcoin in a wallet in case I want to make a purchase.
Why not use a hardware wallet or even just a BIP38 encrypted paper wallet to store it?
Anything else could be stored in a hardware wallet.
I'm confused
I assume you don't need half a Bitcoin for daily expenses, and even if you would want to buy - say - a used car for that money, you could pay from your hardware wallet directly. I use Mycelium on Android for small purchases on the road (usually food deliveries), I keep enough in there to buy what I need quickly, which is only a few percent of half a Bitcoin. I have an encrypted funded paper wallet in my wallet, and can arrange a
$200 emergency loan as a contingency.
Apart from disk corruption resulting from impatience or power failure,my worry was the possible corruption of supporting files resulting from switching between different versions of the core software. My hope is that the core programs are robust enough to cope with any incompatibilities.
I won't expect it to be backwards compatible. If you update one of your Bitcoin Core installations, you should upgrade all of them.