Regular Site Goes Down Auto Switch to Worker Site

So I have a regular site that uses Wordpress and is large and unwieldy (your regular Wordpress type site)
When it goes down (server issues or attack etc…) I’d like visitors to automatically be sent to my stripped back Workers site that has all the essentials for people rather than a Custom Error page.
Is this possible?
How would I implement it?

A worker can “ping” your existing site (send an HTTP request for a small file or script on your Wordpress to check if it is alive), and based on the response, or lack thereof, serve either the resource requested (cached, maybe) or the substitute resource (i.s., a fallback site built on Workers). That will hugely increase latency, though, so the “ping” response should be cached in the Worker for a short period of time (for example, for a minute or five). Another possibility is to have a cron script that pings your Wordpress, and leaves some kind of note (for example, in KV or elsewhere, that is accessible to each Worker fast)