DocHeb is right. The big question is not whether the tractor can move the trailer, but whether it can STOP it when needed. Your tractor can probably get the mobile home rolling and after 200' it will probaly be rolling along very nicely. The problem is stopping 12,000# that has a lot of momentum bult up. I have towed lots of various combos and there is nothing more scary than to hit the brakes and the towed load behind you says "I'm not ready to stop yet". A couple times with that experience and you become very conservative. If you were on a tiny downhill grade of only a few degrees, that 12,000# could probably push your tractor with the brakes locked over 100'. If that does happen, can you post a picture of what 100' skid marks look like that R4's make???