It was his childhood dream to buy Norwood, which covers the opposite side of the valley, and he knows its every nook and cranny.
Since buying it 14 years ago he's planted 40,000 trees and is about to plant another 29,000.
A keen supporter of Boris and Brexit, Mr Hewitt believes the PM made a massive mistake backing a "white elephant" which won't benefit most northerners.
He said: "I want to invite Boris to see for himself. I really believed in Boris. But Boris has let us down."
Norwood is still in its winter garb, tall gaunt pines, birches and beeches reaching for the sky. But it is bursting with life: rabbits, badgers and deer, and countless birdlife including goldcrests and crossbills.
Nearby a kestrel sits on a nesting box and a buzzard slowly wings its way towards the wood.
"This is Killamarsh's Blenheim," declares Mr Hewitt. "I am defending not just for me but the village I love."
He and his friends started building the church two years ago, and two mates lie in the graveyard outside - Sean Bradshaw who was "like the brother I never had" and died at 38, and Christopher Spencer, who was 49.
"They both worked on the farm and we all played down in the woods. When they were dying they asked to be buried there because they loved this spot."
Mr Hewitt's crypt is under construction inside. "It hasn't cost any money at all - my friends are all doing it because they love this spot.
"My friends don't get P45s, they get plots," he jokes.
Inset above the door into the church, which is designed in the shape of the cross, is an engraved stone: "Jerusalem The Kingdom of Heaven".
Mr Hewitt said: "Jerusalem is the centre of the earth - it is in everybody's hearts and minds if you are religious. This is an amazing place - that's why I call it Jerusalem."
Depending what happens they will either rest in peace - or be looking out at a train tearing through a landscape unrecognisable from today.
Later in a 4X4 bumping across muddy tracks in the woods, Mr Hewitt points out the remains of a dam built to hold Woodhall pond, once a feeder reservoir for the Chesterfield Canal, much diminished now but still a substantial stretch of water.
A pipe from the reservoir runs under the wood. It along with old mineworkings, voids, utilities will have to come out, he says, millions of tonnes of soil, muck and clay excavated, the whole valley opencast for the second phase of the high speed rail project.
His business too could go; they want that to use to store the plant for building the line.
"They are not only destroying the wood, the wildlife, they are destroying the future of restoring Chesterfield Canal," he says.
"People say you will be rubbing your hands, I say it's not for sale. If they offered me £50m I'd say it was not for sale."
In the woods Heather Wright is walking her dog Buster. They come here regularly and she is dismayed to hear it is under threat.
"I'm really worried about Britain, " she says. "I am awfully concerned we will be left with no greenspace.
"I think HS2 will be costing a hell of a lot of money. We've managed without it all these years. I hope it doesn't go through really."
A DfT spokesperson said: “Our Integrated Rail Plan is looking at HS2, Northern Powerhouse Rail and our multi-billion pound rail investment programme to make sure we bring their benefits to the North and Midlands as quickly and efficiently as we possibly can.
“We have tasked HS2 Ltd to deliver one of the most environmentally responsible infrastructure projects ever constructed in the UK.
"Phase 2b is at an earlier stage of design and, where possible, the route is being designed to minimise impacts on wildlife habitats including ancient woodlands.”