Have you approached the new owner? Maybe you can offer free plowing in exchange for an area to dump snow? If not maybe there are other farms in the area where a deal can be worked out. Look for a farm that has a drive thats not a pain to plow and make the offer. Good Luck
I have had good luck in the past with placing an add in the local paper advertising for a snow dump. Most places will charge a flat rate or per truck size, (tenwheeler, triaxle, trailer) since the land will not be making them any profits otherwise.
In this area we have had large buildings that are vacant from the economy being so slow and they might be a good place to start. Try contacting the owner(s) of any properties you see without tenants, they are probably willing to listen depending on the length of time the property has been vacant.
We have had good luck just removing the snow from one area of the lot and relocating it to another area. It is amazing how much snow that you can put in one area if you keep stockpiling it with a loader or pushing it with a dozer. By just moving the snow on the property we dont have to worry about breaking any laws,(DEP, state, ect) that you would if you were dumping it on another site. I know that this would not work in all situations, and we do haul snow off site in some situations, in the smaller lots and stuff but we usually haul back to our shop and just stack it out of sight of everyone. Just my two cents