I don't know how much energy you have, but tilling 14 acres or a large portion thereof for a summer to control weeds sounds like a MAJOR commitment, especially with a tiller that can be reduced to a 6" swath. If it were mine and I had a young back I would segment the property into areas that were workable and begin one at a time each year; controlling the weeds then applying mulch, lawn or new plantings to replace the weeds. If lawn is a good portion of the area it may require application of pre-emergent and post-emergent weed controls to gain a handle on the situation, after which a healthier turf can do a good job of weed control by itself. I would bite off a small chunk each year and gain control before moving to the next. Either that or hire a maintenance company to do it for me!
hortster

The entire 14 acres is not landscaped, but its a large majority of flower beds, raised beds, water features, dry stack walls and of course lawn. The rest is fenced pastures for my horses. The tiller is for turning under the weeds in the exsisting beds.