I agree with most every thing that was said. I second making the PVC poles to put under the tarp Slip one in the front seat hole and one in the back and then across to one another kind of like a tent. The more angle you can get the less snow you will have.
Also like Pappy said get you a couple of 2X12s and park it on them. Don't let them set in the wet grass or gravel.
One thing that was not said. If you can get to it pull the water hose off the back of the water pressure gauge after each use. If there is water in the gauge and it freezes it will tear it up. Just don't forget to put it back on next time out lol... Your feet will get wet.