Great question. And some good poking from your fans. Yes, adequate recovery and rest is very important. Especially in the long run. For certain “events” whether it be racing, doing the ToS or some other crazy adventure we do tend to make exceptions. And there are limits for sure.
What will the ToS do to your body? Well, like Mac says, " It depends" but overall if you are relatively fit and you have tapered a bit going in, you’ll be fine. You will also be, hungry, sore and tired. But when you get to the end of the tunnel just make sure you fully rest and recharge before returning to normal training. The real danger is continuing to dig a whole afterwards.
Now, for the voice of reason that we often ignore- we are in the middle of a global pandemic- so, if you feel more than just tired or you are compromised in any way, you should bail. If you still want to participate, reduce the intensity and noodle along or just get on the couch. Do NOT compromise your long term health to do the Tour.
If however, things are good- dig in. And after each stage, dig in. That means add an extra serving to your meal and get some extra sleep. Just like @emacdoug said, “Just listen to your body so you know when/if to dial it back and by how much - so you can finish but still do it in a healthy way.”
As long as you are still having “fun” suffering you are good to go.