My husband and I went to Midwest in 2008 for a week. I don't know if we will go back. If it was closer to where we live, we would definitely go back for a couple of days or so. We liked it OK. The trails were pretty, but not challenging at all, at least not the ones we rode. We don't like dangerous, but do like some decent hills. Also, if you don't buy a permit, ($5 per day per person, I think), to go into the Forest, there really isn't enough riding for a week without riding the same trails.
We liked the campground. We were parked backed up close to the stalls where our horses were and were able to keep a close eye on them. The store is nice, too.