You should save up and buy a small tractor. Something like a Ford 8N or an Allis WD45. They are 40-60 years old, but will hands down outperform an ATV when you are trying to do groundwork. Another thing about old tractors, they don't lose their value like something new. I've got a '63 Allis D17 and a '73 Deere 830. Both are working strong, and I don't anticipate anything going wrong with them in the next few decades.
Buy a 2 bottom plow and a 5' disk. Shouldn't be more than 5 bills. That'll do 90% of your plot work. If you know how to weld, you can make other implements like a boom pole lift, 10' sprayer, subsoiler, etc.
Once you have a tractor, you'll find new uses for it and tell yourself "I don't know how I've gotten along without this".