What do we do if we don't have a full party?
There's a lot of ways I can mitigate if we're short a few players.
1) Simply adjust the number or levels of creatures encountered.
2) Treat recovery time differently (i.e. instead of healing daily you heal hourly)
3) Grant bonus action points at the beginning of an encounter
Adjusting encounters would work but it is more on the fly changes you would need to do to the campaign. Changing anything thing else would change the nature of the campaign, in my opinion.