You might try to talk to your neighbor before calling the law. Then if you ever had to call DNR for obvious poaching you would not be the town crier.
Why? Only one who is going to know is going to be DNR. I soibt if a warden showed up they tell the hunters/poachers "oh yeah, they guy in the house over there called us".
Frankly I'd call DNR. It sounds like poaching. The distance is likely to be safe, especially if they are using stands. It is possible they are just uneducated abou the hunting laws, which safe distance there is no excuse. That said if they are willing to break one hunting regulation/law, what other ones are they breaking it willing to break????