Well, FD, I think you are correct in identifying 'mindset' as something you can positively affect when practicing forced landings. Statement of the bleeding obvious time - the thing that kills you is hitting the ground, and I'd guess that means it helps to be in the right frame of mind when you are close to the ground, i.e in those final 50ft. If you've never been down there how do you know how you will react? Most people have only ever landed on tarmac and even a nicely mown field will cause people to panic if they have never seen one close up. Take them down and show them it's not a death trap, and if they are down there for real one day they will be able to concentrate on a proper final approach and flare.
I never really appreciated this until I started doing engine out practice in a tail-dragger. In a nosewheel spam-can I'd always have this dread in the back of my mind that I'd get the nosewheel caught and flip over. Going down to 20ft in a tail-dragger and actually setting up for the landing made me realise that even a really nasty field was totally survivable. So I'm now believing that if the engine did fail I'd not be worrying myself into a fatal mistake in those final 50ft. I would not have known this if I'd never gone below 500ft.
Another reason to fly a tail-dragger, not that you need many, but they are designed to hate tarmac so you will surely do better in an off field landing flying one.