Bikerpelli fills very quickly every year - in 2016 both trips were full in under 20 minutes and it gets a little faster each year.
The best bet is to get in right at the opening bell, 10 am Colorado time or noon EST.
You may register additional riders but it will slow your progress & lower your chances. How much? We can't predict that. You're probably fine registering 1-2 extra people but more than that is a gamble.
To register addt'l bodies you'll need the following info from them in advance -
Name(can't be changed later)
Address Phone(cell # please) Email address(absolutely VITAL!) Date of Birth
Emergency contact name & phone Jersey size(gender-specific, can't be changed later) "Is this your first-second-third-fourth-fifth Bikerpelli?" "Did you register or ride Bikerpelli last year?"
The bold items are what we're most concerned with, other stuff can be edited later if needed. You can save some time at checkout if you setup a user login with Bikereg.com here.