It really depends on what you're normally used to and what your aim for the century is.
If a century is a big deal for you (that isn't meant to be patronising) I would think that your training schedule will have been slowly building up the miles over the previous few months, throwing in occasional shorter and sharper rides for a bit of variety (never underestimate the importance of speed work while building up your endurance). Your last longer ride will have been 60-70 miles a couple of weeks before, probably with 40-50 the previous weekend.
Your body will adapt gradually to incremental additions and will keep hold of the new abilities for a while. Don't be afraid to do nothing in the week before if that's what you feel like, you won't lose all ability (even stopping your bike commute if you do that), but utterly resist the temptation to cram in any sessions you feel like you've missed. As others have said, it's too late to fix your training schedule now.
In many sports there's a saying that a start to a race won't win it for you, but it can surely lose it for you if it's bad enough, and this goes as well for the week before a long event.
My advice, especially if it's your first century, is to rest well, eat well, hydrate well. Try and do a short-ish ride (25-30 miles) a few days before, at the very least to make sure your bike is ok.
And never, ever, do something new and untested to your equipment on race day: that includes new shoes, new shirt, new power bars, even new bar tape. You might get away with a new bottle, that's about it.