Lake Maloney has electric only hookups and is first come basis. It's about 6 miles south of North Platte. Don't know how long your stay is for, but the lake is very nice. I imagine the summer weekends fill up. If you're coming in during the week, I wouldn't think it would be a problem to get a site.
http://www.ngpc.state.ne.us/parks/gu...sp?Area_No=112
Lori