The McNabbs opened their bed and breakfast in 2018, with the business name inspired by the Banjo Paterson poem Mulga Bill's Bicycle.
The cycle trail passes close to their property as it skirts around the back of Kaikohe Aerodrome.
They spent close to $20,000 turning a sleepout into a comfortable four-bed cottage with the money going on furniture, carpets, extra rates and jumping through resource consent hoops.
They were told they needed a resource consent, among other reasons, because of noise generated by the nearby airfield — even though they're lucky to see one powered plane a week.
Bruce McNabb said pre-Covid most guests were from Auckland, with a smattering of other Kiwis and overseas riders.
Bookings took a dive due to the pandemic and Northland's extended stay in the red setting, but now the recovery was threatened by the trail's partial closure.
Any time cyclists called to make a booking, he checked that they knew they could no longer ride from coast to coast. Some changed their minds right away.
''If I were a cyclist from outside Northland, I wouldn't come here to use an incomplete trail. It's no longer coast to coast. That was the whole idea, the whole romance of it. That's disappeared. The grown-ups in the council and the railway trust need to get their heads together and sort it out.''
The council is currently looking at an alternative route that would send riders from Ōpua to Kawakawa via Oromahoe Rd and Whangae Rd.
''But there's no way I'd want to ride that. It's gravel, it's windy and hilly.''
McNabb said other business owners he had spoken to had seen their income drop by 75-90 per cent.
They were better off than many because they could seek other guests. Businesses offering bike tours and hire depended entirely on the cycleway.
McNabb said more than 31,000 cyclists used the trail in January-March 2021.
If half those were visitors from outside Northland and each spent $500 in the region — an estimate based on their own revenue figures — that meant a spend of more than $7.5 million in those three months alone.