Update: The radiator did have a lot of thick dust build up. I have seen it a lot worse (like the whole thing packed with grass after bush hogging) but i sprayed air from the back side and cleaned a lot if it out.
I ran the rototiller again on the 75x75 area. No overheating at all however i did have another sudden screeching halt to everything. It turns out a rock got lodged in the tiller and apparently the slip clitch on the pto shaft is not adjusted properly so it abruptly stopped the whole tractor. I am thinking now that perhaps this is what happened earlier and the siezing up was not due to overheating. Granted still a potentially disastrous event to have the slip clutch sieze but i will try and adjust that and keep a close eye on all fluids for signs of blown head gasket.
Thank you for everyones help on this issue.
As others have said, you need to adjust the slip clutch on the tiller. If the tiller slip clutch sticks and does not spin to prevent the engine from stalling you are about to one day find out what "Splitting" a tractor and the associated expense is.
I know a gentleman who went to an estate auction and got a "Steal" of a deal on a tiller. He thought it had a slip clutch and it didn't, it had a high grade bolt instead of a shear pin. He found a couple of rocks and now is saving the money to split the tractor and pay for the repairs for the internal damage that was done.