That makes a lot more sense. I had this image of you picking up the contract to do all the neighborhood soccer fields.
For weed control at the edges, take a look at Casoron 4G. Granular you apply once a year, just before a good rain. Harmful to some trees.
ZTR's are hydraulic. That cuts your fuel efficiency by 50% Tractor is likely diesel. Gives you another 30% On the other hand, that triple PTO nickles and dimes you with a bunch of 90% efficient energy conversions.
A 60-80 acre complex. All clear fields? If not you will still need to deal with the trees. You may still need a ZTR as an edging tool.
As a suggestion: splurge and buy a camera that points backward. This will save you a bunch of sore neck watching where the edge of the mower is..