After the fun of planning and building the restaurant, they then had to establish and develop a business "from zero" in a relatively isolated spot, which had been quite a challenge.
Initially, the plan was to build a small cafe alongside the Riverstone gift shop complex, which was established by Mr Smith's mother, Dot.
But the couple's background was more restaurant than "coffee and cake" and the project became more ambitious.
The restaurant, which opened in November 2006, was still a work in progress, with its extensive kitchen garden just starting to come on stream. There were also about 80 hens, supplying the restaurant with free-range eggs, and a herb potager area was being built.
Having control over the produce they sourced, along with using food which was ethically produced, was very satisfying, Mr Smith said.
One of the things they hoped for, as a result of winning the award, was an ability to attract more qualified staff. It was difficult to draw skilled and experienced staff away from the "main centres and bright lights".
While the award had lifted Riverstone Kitchen's profile, there were still a lot of people who did not know it was there, including some at the awards function. "I think they do now," Mr Smith said.
The couple, who have two children, Jordan (3) and Noa (5), have two days off a week. Striking a balance between family life and work was a personal goal for them, Mrs Smith said.
They enjoyed the country lifestyle and were in the enviable position of having a one-minute commute to work.
The restaurant catered for everyone, from family groups and farmers to truck-drivers and two pilots who decided to fly down from Wellington for lunch one day "because they could".
While not a fine-dining restaurant, they did try to incorporate elements of what customers would expect in a fine-dining restaurant, such as perfectly polished glasses, and other details, yet a truck-driver could call in for a scone.
The couple knew the publicity following their success was priceless and that there was now a huge responsibility to live up to people's expectations.
"It's a big responsibility but we're up for the challenge," Mrs Smith said.
The experience had been very humbling, Mr Smith said.
While it had been a slightly surreal week for the couple, they did not have much time to bask in their success.
On Thursday, Mrs Smith was up at 4.30am doing the laundry, while her husband was baking bread, and both were back at work in the restaurant later in the day. The phones were ringing red-hot, with people making bookings at the country's new top restaurant.
They returned home from the awards function in Auckland to a restaurant filled with flowers and cards.
There had been "so much support" from locals, regular customers and even people who had never dined at the restaurant.
"It's been a great week. The best thing is it's great for all our suppliers. I think it's just a win for good food, basically. Good honest food.
"I'm proud of all our suppliers ... our win reflects their hard work, I guess, because their fantastic produce makes our job easier," Mr Smith said.
It had also been fantastic for their hard-working and loyal staff as everyone involved at the restaurant played their part in its success.
"We're just the face. You can't do it by yourself, bottom-line," he said.
