Nebraska Atv Trails

Good ATV trails around the area of Nebraska?
I am preparing to graduate from college and I thouroughly enjoy riding ATV. I own a ranch new and my father owns a Kodiak 450. I would like to take a short vacation in a picturesque place, and also somewhere that my girlfriend could join before going to work full time. I was looking at the Nebraska National Forest or something. I will be towing two quads so you do not want to go somewhere far within 3 or 4 hours of Lincoln or Grand Island would be good. If anyone has any experience with quad routes nice i would love to hear from them. I'll go in early to mid May this year. Thank you all.
http://www.atvfan.com/Nebraska_ATV_Trails/ hope this helps, the place I go riding trail is located in the CO Taylor Park, absolutely beautiful view, but is about 12 hours away from Lincoln!
Cedar Run ATV Motorcycle trail at Harlan County Lake