Wow! Wish we had as much snow as your pics show. This year is really slim so far. I assume you are grooming for snowmobile traffic, judging by the sled groomer you are using. Pulling it with the tractor in early season is a good idea. I bet the loader comes in handy for trees etc.
I finished the basic roller and chassis yesterday at 3 pm, and went out and pulled it over about 8 miles of trail by dark. Nothing broke, and I hit some big darn rocks in places too, that had the roller jumping off the ground. We have only about six inches of snow on the ground now. The Gator is still on wheels and tires, so I let the air pressure down to 8 from normal 15 psi in the Big Horn tires, and went for it. It pulled it very well in FWD. Occasionally I would lock up the rear axle for extreme uphill stretches. Once the tracks are on, the effective gearing is changed to make the rig slower so it gains power somewhat. The traks take some power too of course, but should make up for that with great traction and flotation. I traveled an average of about 7mph, which worked well for the roller action. Any faster and the snow just flies too much and the roller leaves less of a nice imprint pattern in the snow. Any slower is too boring.
I will add more weight to the chassis after I am able to get the tracks on the Gator. For now it is heavy enough, but could do more imprinting for a deeper freeze if it weighed more. And with the tracks, I can pull more weight. Also, I have room in the frame for some more tools to mount, and have some ideas and lots of scrap items to choose from, so that will evolve.
Pics soon hopefully.