Think I'll post my $0.02 now...
So the chances are, IO will only be interested in your last 5 yr travel history, which of course you will have declared on your N-400 application. No problem right? Well maybe. The issue is that USCIS has a duty to establish that your GC was obtained lawfully and held properly since its issue. Under most circumstances they rarely ask much more about this during interview as they usually already have the I-485 paperwork in front of them. In your case however, it sounds like there are significant issues with your travel dates prior to 2001, and if these are recorded in your passport, you might have a problem.
Any chance you have already, or might be about to, renew your passport?