I pulled my M750 trailer with my F450. Did it do it, yes. Did it do it safely, NO!
Flat towing the 1079 with a 250 is asking for trouble, not to mention IP/GP will not let you off the site with that setup. If you did manage to leave the site it's a guarantee the MP's will stop you before you make it out the gate.
Sorry I haven't gotten back with you. Been swamped with VA appts.
The hitch of the 250 is a class 4/5 2", not rated for the dry weight of the 1079. When you stop you will have the full weight of the 1079 pushing the 250. The engine is capable, it's the brakes, frame, everything else that isn't.
Don't do it. I was going to flat tow a deuce /w shop van body with my 450 and glad I didn't. I know the truck would stop it as I've been in similar situations where hauling heavy and lost trailer brakes, it's just a matter of safety.