A chance to leave a legacy that will last well beyond their lifetimes. That is what Paul and Rowena Williams want.
But there is a hefty price-tag on turning a historic mansion and grounds into a five-star destination - £20m.
The couple remain undeterred and have opened their doors to thousands of visitors to share their plans for Plas Glynllifon, near Caernarfon, Gwynedd.
However, challenges remain - some controversial - including who owns and runs the estate's gardens.
Mr and Mrs Williams bought the former home of Lord Newborough in 2016, and were well aware of the massive task they were embarking on.
Years of neglect meant much of the 102-room property was semi-derelict, after the collapse of a previous wedding venue venture in 2013.
"Grim... the smell of damp and mould and must was all around - severe water ingress everywhere," recalled Mr Williams.
"The stench itself was a little bit off-putting, to be honest," added Mrs Williams.
Initial investment was priced at upwards of £6m as the scaffolding went up and the workmen went in.
"Before we purchased it, we spent four days surveying it, so we knew what we were letting ourselves in for," explained Mr Williams.
They hope the restoration will be complete by 2020 - a year ahead of schedule.
This week, the couple threw open the doors to the house and far more than 2,000 people flocked to see what they had been doing.
They were given the chance to view restoration in the the south wing of the mansion, where the staterooms and some of the bedrooms are nearing completion.
Each room takes a different theme, with antiques and artworks sourced across the world, all aimed at recreating the opulence - if not outright decadence - of the mansion in its 19th Century heyday.
It was also a chance to hear about the next steps for Mr and Mrs Williams - and those are not just about the mansion house.
They could be potentially controversial.
The couple have put forward a plans to acquire the pleasure gardens the fan out across nearly 30 hectares (70 acres) from the mansion.
Parc Glynllifon includes miles of paths through woodland, with a slate amphitheatre, a deserted fort, a mausoleum, hidden memorials, fountains and artwork.
There is even an old militia fort - Fort Williamsburg - dating to 1761, built by Sir Thomas John Wynn in the estate grounds when he became Constable of Caernarfon.
Under the proposals from the Williams's company, Plas Glynllifon Limited, would take ownership of these areas and then establish a 999-year lease, which would pass to a community interest company.
"We're investing a significant amount of money in this property at our risk, and we just want the restoration to extend to the ground, as it really should do," argued Mr Williams.
Many of the features are owned by the agriculture college Coleg Glynllifon, part of Grŵp Llandrillo Menai further education body.
The park itself is owned and maintained by Gwynedd council.
The Plas Glynllifon owners said they are in talks with both the college and council about their proposal.
Mr Williams said the college, alongside the council and local community representatives, would be responsible for running the new not-for-profit firm running the park.
"If we can obtain more land, we can really have a proper visitor destination here, with a wider experience."
A wider experience - but at what cost?
The Williams recently commissioned their own report into the state of grade-1 listed gardens, and the 20 or so structures dotted across the park.
According to that survey, about £14m is needed to restore the gardens and buildings to their former glory.
It would see another third of the park re-opened to the public - areas that have been shut due to public safety fears.
The question is - where will that sort of investment come from?
Plas Glynllifon is not the only recent purchase Mr and Mrs Williams have made.
They have taken over running the Seiont Manor country house hotel on the other side of Caernarfon, and they have purchased the derelict Plas Brereton and Ty Coch properties just outside the town.
Mr and Mrs Williams want to turn Plas Brereton estate into a luxury "fishing" village or hotel development, with residential properties too.
They said those are the "enabling projects" that are the key to revitalising Glynllifon.
"We've got a substantial mortgage at the moment. If this business was to open with that mortgage, it would not be able to sustain the repayments.
"The enabling development, it will generate the capital to actually fund the wider strategic plans."
But places like Plas Brereton and Plas Glynllifon have a worrying history of failure when it comes to commercial ventures - what makes Mr and Mrs Williams sure they will have success?
"We've got the passion and commitment for one," replied Mr Williams.
"We've got the expertise - we've been in the hotel industry now since 1999.
"I wanted to do something that was really stunning - and this is a once-in-a-lifetime opportunity to restore something that is almost lost."