I drive our tractor for haymaking. Not especially difficult (depends on the job), but are large powerful machines. Also depends on the terrain, luckily ours is flat, 'undulating' I don't like.
Maybe you could have a word with the contractors, they should have the answers to your questions. Ask if you could do an accompanied test drive (off road) to see how you take to it (some tractors, like ours, have a second smaller seat in the cab).