I also find the discussion about articles interesting. I’ll take your comments one at a time:

“On country road in mid-Virginia” Maybe it’s an American preference, but I think “a” shows that it could be any country road, where no article implies some particular road called “country.”

“The cyclist pulls up another hill” You are right in saying that the cyclist is a particular person and that she does not pull a hill, but rather ascends it or pulls up it. The cyclist is, as you say, at the center of the poem, so on that basis I could agree that “the” should be used. You say that she is “not just a cyclist,” but really she is. I want to show her as nothing great or worthy of separation from other cyclists.

“Past the house with mammoth lawn. The use of 'the' here specifies that the house is a landmark rather than just any house with big lawn.” But really it is just another house with a big lawn. The country people of Virginia take pride in their lawns. Sometimes I pass a run-down house trailer with three acres of mowed grass and a fine garden.

“Visual input does not soothe tired eyes.” I often find the opposite to be true when cycling. The sight of a well-kept dairy farm soothes the strain on my eyes that has come from staring on the road, avoiding death by coal truck or passing car.

“the cows look up,” Here I agree that the cows are almost as central to the poem as the cyclist, but they are not particular cows, and therefore the definite article “the” seems inappropriate.

“’Bovine eyes’ sounds wretched.” I used “bovine” to avoid what I thought was the wretched sound of “cows.” Maybe I made it wretcheder.

“’Free from fence and milking’ sounds terribly clunky.” I admit to often sounding clunky. The sound of poems is a thing I’m working on.

“What is wrong with she pants (UP) a lonely hill instead of lying in the shade.” That’s a good suggestion; better than the way I had it. I don’t like “up” though – sounds clunky. I’ll change it to ‘she pants a lonely hill / instead of lying in the shade.’
“Anthropomorphism is dodgy at the best of times but even if we attribute thoughts to the cow, why would it assume from seeing a human cycle up a hill that she was 'free from milking'” Those bovine eyes stare at me with the provincial look of someone who always lives by the norms and never ventures. Such a person complains about the milking tubes her owner attaches to her tits twice a day and about the fence that holds her in, but she never really wants it any other way, because that’s how dairy cows live.

“From their perspective you are behind a fence too.” From their perspective, I am free from the fence, which they know every inch of.

“The cows rebuked” Maybe I didn’t make it clear, but the cows are not rebuking, the cyclist is. She preaches to the cows - a daft idea, perhaps, but each to their own.

“I would say in the alcohol of afternoon, then you have a metaphor for the weariness and blurriness. As it stands it reads that legs draw concentration like alcohol draws concentration.” Actually, that is what I mean. Working legs draw blood from the brain, which in the weariness of afternoon, after cycling most of the day, has an effect on the brain similar to drunkenness. Still, I like the way you phrase it. I’ll change it to “In the alcohol of afternoon, / legs draw concentration,”

Thanks for your comments.