Indian Cave near omaha, NE (i think), I have heard is great riding for the advanced rider/horse. Very hilly and has rougher terrain. Never had a chance to make it out that way. Rock Creek Station near fairbury, NE is a good one but its near the kansas border. Very historical as it was a lay over for the oregon trail, and theres some wild bill hickock history their as well. I have ridden there many times and it has quite a few good trails for every level rider, and you could ride for days even though the park is about a square mile.
My In laws live up near souix falls on an acreage. I would love to haul the horses (only 6 hours from where we are in KS.) up there and see what they have for riding:) I LOVE LOVE LOVE SD. When my husband gets out of the army we are considering moving up that way.
I am down! But it definetly be after this baby is born (riding is starting to get uncomfortable for me:/ ) and hopefully fuel prices go down! I know my husband would be ALL for hauling the horses up there. Where are you at?