Airline pilot Chris has raised more than £12,000 for Samaritans and covered more than 200 miles.
Chris Fordham plans to run through Gloucestershire, Wiltshire, Oxfordshire and Berkshire this week.
The RNLI says the group called 999 after realising they were cut off on Easter Sunday.
Vicky Curtis-Cresswell has been unable to claim the coastal home due to planning issues.
Edward Stubbings, from the National Trust, says seeing the seals is a "spectacular wildlife event".
Councillors give retrospective approval for unauthorised work on the £6m raffle prize.
A local committee will have the final say on whether the £6m property is legal.
The firm is fighting to avoid parts of the mansion being demolished.
Forestry England says repair work will create a larger beach area and prevent further erosion.
