Bob a PTO trencher is going to cost around $ 6,000.00 or the chinese trencher is about $ 1,500.00 .Daylight and dark in the differences and quality.You can buy a half decent used trencher at a equipment auction ,use it and then resell it for about the same money.That may be a better option.Or save up your trenching and rent one for the weekend,in good soil you can dig hundreds of feet per day, then cover it with your box blade and loader
Tommy
Affordable Tractor Sales