IMHO, do not try starting farming from the beginning. My original family farm, combined with my land and brothers land is about 1200 acres. I have a full time job and mostly weekend farmer. My brother has full time job but has much more flexibility in his job and can take times as he needs it. Strongly recommend renting out all the acres to begin with. It would seem the OP has no experience in this field. No offense but starting with "what kind of tractor to buy" and asking TBNers is a little on the wild side IMHO. Why hasn't the land been worked for many years? That alone makes me nervous about the land. Will it require lots of work to get it back in production? Is the soil poor? Is it overgrown? Where is it located? Are you willing to buy a tractor, planter, sprayer, fertilizer machine, cultivator, disc, chisel ect? Do you know how to maintain much of this equipment? No till verses tilling the land requires different equipment. Will you need to have the soil tested? Do you know the seeding rates, fertilizer rates, spraying what chemicals, which chemicals, when to spray? Honestly, farming corn and soybeans for 100-150 acres of land it really a waste of time and not profitable. The overhead is just way to high. Why are farms getting larger and larger? Because they can use 1 relatively large machine to do many acres. Our 1200 acres uses primarily 2 tractors (245hp and 125 hp), 1 16 row no till planter, 90' sprayer, 1 fertilizer machine, ect. The efficiency of a farm actually goes down when they become over a few thousand acres because now they need 2 planters, more expensive sprayers, more tractors, ect to make the next level of production and they don't really have the land to make it as profitable for all the equipment.
If the OP does not want to rent the farm land, try share cropping the tillable land. In my area, the owner puts up the land, pays the taxes and pays half of the input costs including fertilizer, seed, chemical ect. The other guy provides all the equipment, fuel, labor and does the harvesting. OP assumes some of the risk and potential reward. This would also allow the OP time to find equipment, see how the farming is done and give time to decide if this is a viable venture.
The pasture maybe a little easier to start with less initial output but does the OP know how to care for the cattle? Will the cattle be in the pasture all year? Will they have to be fed in the winter? Will it be cow/calf operation, feeders ect? Does OP know how to care and look out for the cattle. Facilities to vaccinate, or treat animals? Do you have means to haul the cattle when needed? Cattle require frequent checking. 1-2 dead or sick animals really eats into the profits. How good is the pasture and fence? How many head/acre can it support? I rent out some pasture. So much $ per head/day. Renter maintains the fence but I supply the materials.