Mr Johnston and wife Heleen have been operating their family-owned garage for 33 years and could be among those who would do well financially from motorists using a new, more direct route between Milford Sound and the West Coast.
Haast-Hollyford Highway Ltd, the company behind plans for the $250 million toll road, announced on Saturday it is likely to apply for resource consent in April.
• Slideshow: Road proposed through Haast wilderness
Like others spoken to by the Otago Daily Times in the Haast-Jackson Bay area at the weekend, Mr Johnston had concerns about how the road might change a part of New Zealand he regards as paradise.
''I wax and wane,'' Mr Johnston said.
''I'd hate to see it cause the loss of a nice wee corner of paradise but I see the trends for my own sort of business.''
While Queenstown was increasingly becoming a tourist hub, fewer tourists appeared to be venturing further afield.
''I think that road would make us part of another loop.
''And the fact somebody else is paying for it, and it's going to be a toll road, makes it a little bit better for me as well.
''The simple fact is the taxpayer is not going to be lumbered.''
Jackson Bay crib owner John Searle, of Cromwell, says he has mixed views on the plan.
''It's sort of our playground down there for hunting and fishing and we don't really want to see it get opened up.
''It's probably going to be good for locals ... but this is where we come to get away from it all.
''It just scares me what it's going to do to the area.''
From a tourist-industry perspective he could see a road creating a loop including Queenstown, Te Anau, Milford Sound, Haast and Wanaka as ''probably quite a good idea''.
''But, do we have to have a road through every bit of New Zealand?''Two English tourists on their second visit to Jackson Bay, Lynda and Roger Goddard-Coote, were firmly against the road idea.
''We love it here and we would hate to see it spoilt with more people than it can handle,'' Mr Goddard-Coote said.
The first 20km of the 180km route, alongside the Jackson River, already has a narrow gravel road along it.
The only person encountered there by the ODT on Saturday was Perth man John Hibbs, who has spent the past three years walking 10,000km along trails all around the world.
He suggested a walking-biking trail rather than a road.
''I think it would be hugely popular.
''There are so few true wilderness areas.''
