Height on the door is a concern for me for a tractor.
https://www.prolinetrailersales.com/enclosed-trailers/enclosed-car-trailers
Enclosed Car Haulers is what you need, the side door or escape door is really handy getting out of a car, would make exiting from the front of the tractor possible for you.
I would say 14ft would work but just barely, I feel you would like a 16ft better for hauling a tractor, my buddy has a 16+2 equipment trailer and my 4320 with forks didn't fit within the 16ft deck, I had to have the forks hang off the front of the trailer to get the rear tires up, I was also hauling back a round bale feeder which took up every last inch the tractor didn't.
With enclosed you don't have the luxury of letting stuff hang over the front or rear of the trailer, it has to be 'packed' inside.
For an Emax I feel 18 will be too big, I feel 14 will work but be cramped, I would suggest 16ft. If you plan to get a bigger tractor or want to haul an attachment behind the mower that adds another 5-7ft on the tractor. Which is why a longer trailer would be really nice.
Keep in mind the trailer will be 2500lbs-3500lbs I would guess which cuts what you can haul with 3500lb axles, with a emax that's not as much of a concern, with a bigger tractor I would be if you ever upgrade.
Edit: just looked it up, says the mahindra 22emax is around 8.5ft idk if that's with or without the loader, if the loader was 4ft more with a bucket were at 12.5 ft, you could do a 14ft but I personally would like the extra room to haul more than just the tractor in the trailer, with a 16ft would could have a rear blade hanging off the tractor comfortably, worst case is take a tape measure, get a really accurate measurements of the tractor width, height and length, go to a trailer lot and look around and measure on the floor of a trailer the dimensions of the tractor. And chose the one most comfortable.
Hopefully folded ROPs will clear an enclosed trailer.
