He said he was expecting "brutal" conditions but would be "battling on", with Storm Darragh expected to bring strong winds to western parts of the country.
"To see schools come out and understand what MND is, to see schools talk about friendship and how to look after people properly, is a wonderful message for us to pass over.
"But it's the money that's going to change things," said Sinfield, who agreed to remain as assistant coach for the England rugby union squad in October.
On the final day of his Running Home for Christmas challenge, the Oldham-born star is set to run from Old Trafford to his Saddleworth home in the Pennine Hills.
The first leg of his seven-day endeavour began with a run between Liverpool and Wrexham, in north-east Wales, on Sunday, followed by a 60km (37-mile) run between Gloucester and Bristol.
Accompanied by a team of support runners, Sinfield then completed a series of 50km (31-mile) runs in and around Belfast, Glasgow, East Yorkshire and the East Midlands respectively.
He has so far raised about £700,000 for six MND charities to help tackle the impact of the incurable condition, which affects a person's brain and nerves.
Burrow, who was married with three children, was diagnosed with MND in 2019, after a successful rugby career which included eight Super League Grand Final victories.
He also won 15 England and five Great Britain caps.
Burrow died in June, at the age of 41.
Route for final day