ENDSLEIGH HOUSE, the 19th century Milton Abbot estate, is applying for £3-million of National Lottery funding for restoration work.
It is also seeking another £800,000 of matching funds from other sources for the project.
A charitable trust owns the house, and leases it out as a hotel for fishermen, as well as its 60-acre grounds.
The trust is in the third year of a ten-year programme of works, the estate having been left in a state of disrepair since the 1950s.
Lt-Col David Hourahane, secretary of the Friends of Endsleigh, set up this year as the trust's marketing and fund-raising arm, said they needed to be able to show the Lottery that they could provide the matching funds in order to be awarded the £3-million next autumn.
The trust met last week to discuss the appointment of a chairman of its appeal committee.
Endsleigh is at present little known outside the salmon-fishing fraternity, but the trust hopes to turn it into a tourist attraction.
Lt-Col Hourahane said the aim was to attract 5,000 visitors next year. Marketing literature is being produced for distribution to tourist agencies.
It is hoped to offer a joint ticket with the National Trust's nearby property at Cotehele.
The trust received £1.25-million from the Lottery's heritage fund and raised £250,000 of matching funds for its first phase of works, which will be completed next summer.
The property is regarded as of national importance, containing 13 Grade 1 listed buildings, which have to be restored to strict standards laid down by English Heritage.
These include the hotel, built in 1810 by Wyatt as a fishing lodge for the Dukes of Bedford, a greenhouse, a stable block, a brewhouse, an enginehouse and a Shell House, a summerhouse overlooking the River Tamar encrusted with shells.
The gardens, designed by Humphrey Repton, are also of outstanding quality .