I drove up there from the Round Lake, IL area in mid-April to check it out. I had planned to bike the trails, but the biking trails were closed, as were the horse trails (probably due to wet conditions). Be aware of the use fees: $10 vehicle, $4 trail pass fee (bikes, horses). Cheaper for Wisconsinites. 3 stars for now; didn't spend enough time to really rate it. Just wanted to pass on the info about fees and trail closings. They have a phone number, 262-878-5600. Call ahead. 26313 Burlington Rd., Kansasville, WI 53139.
Went up to Bong on a Saturday in the fall. Be warned; during hunting season you are restricted from hiking to certain areas. Still had a nice time, hiking was OK, but could only hike the smallest loop in the trail system (green trail). Would like to give it a try when all trails are accessible.
I have hiked all the trails at Bong. The blue loop is the most picturesque and is over 4 miles. The red loop is the longest at 8 miles with the orange loop at about 6 1/2 miles.
The hiking is gorgeous in the fall. Summer is also a good time to hike these trails.
I hiked the Orange Loop which ended up being 6.7 miles. There are many different trails with the Red Loop being the longest of them all at approx. 8 miles. The trails go through many wetland areas so bring/wear bugs repellent if you do not want to be swarmed by mosquitos. Otherwise, the trip was lovely and while hiking there was no one else on the trails. Definitely a must if you desire a quiet and peaceful hiking experience.