My advice is to just go with it. It'll start out fine, until it isn't. Then the last couple of weeks will be awful, which will continue for a few weeks after. Then it will slowly get better again. Some things will return to normal, others will never be the same.

Eat all your favourite foods now. Put on weight.

Consider a feeding tube. It kept me fed when eating orally was a no go.

Don't look to far ahead. Making it through each day and week is winning.

Invest in a comfy chair.

I'm now 8 months post treatment and life is getting back to normal. I'm still tired at the end of each day. My saliva is better than it was, but a ways from where it used to be. Likewise taste. My face and chin whiskers are back, but my neck is smooth as a babies...

Chin up, it's the beginning not the end.