Greeley Trib has details about parking and shuttles here: http://www.greeleytrib.com/apps/pbcs.dll/article?AID=/20041024/NEWS/110240092
The website for Island Grove claims that gates open between 6-6:30AM instead of 7AM - http://www.ci.greeley.co.us/2/PageNewsDetailsTicker.asp?fkOrgID=52&TickerID=1