The place near Racine with 600 yards is called "Racine County Line Range". It is a military built range, and is member only for open shooting. They have regular highpower shoots as well as league shoots. The deal is membership dues plus hours worked on the range for upkeep. If you can afford the time the dues are very reasonable. There are 2 skeet fields as well as a 300 yard range, 100 yard range and pistol range. I am not a member. There are usually some guys shooting skeet there on Saturday mornings, and the gate is open. I would recommend you drive down and talk to them about membership and details. It is just south of the Oak Creek powerplant, take Hwy 32 to 7 mile road, 7 mile east about a mile, the entrance is easy to miss but it JUST west of the RR tracks about 100 feet. First set of RR tracks BTW.
For 100 yard rifles the Wisconsin Sportsman is just off of I-94 at Hwy 11. Go west on 11 about two miles. The entrance is right across from the trailer park entrance. Open Tuesday and Thursday nights, and Sunday afternoons. Dues are nominal, and per use fee for ranges. It is open to non-members as well, but per use fees are higher. 25, 50 and 100 yard rifle, two trap and one skeet field. I am a member and it is a great value.
Kenosha Conservation Club Bristol Shooting Ranges has a 100 and 200 yard range for rifles. They have regular highpower on reduced targets. Range fees for non-members are kinda steep, and I do not know what membership costs or entails.
I hope this helps. I have been reading over here for a while and finally had something to contribute so I registered LOL.