There should be some easy too see chain holds, I dont know a mill that aint got em. Make sure the cutter teeth are as close to the deck of the trailer as possible, raise up the front and rear moldboards and visually check till your good with it and chain the sucker down.
Some people like using the tracks as chain holds too, being its a four track thats a good go if you cant find D rings or holes for chain hooks. Good Luck and send pics, I havent heard of anyone buying those.
If you had to hold the override button down just to load it, I would suggest checking the oil before unloading it. It is probably 1/2 a gallon low if the engine is shutting down on that short of an incline.
IR made some of the better mills way back when, I remember getting our @sses kicked on sq yds by a 7ft cuttin one back in the early 90s.
IR was also sued in and lost for around 17 million back in the 90s as well, something about the machine backed over the groundmans foot. From what I hear now they have some pretty annoying safetys on the track travel control when its up out of the ground.
Then again Wirtgen are annoying as well with that travel control speed cut when the tracks are turned more than 5 degrees either way.
In the cut, I'd like to see an IR/Volvo against RX500/W2000/PR600, with a good operator that knows how it would probably keep up if not outright beat them. IR had a great gear drive system which put max HP to the ground.