A spokesman for Parker's promoters, Duco Events, said the school visit would be more inclusive than was first proposed.
At the start of August, Whanganui High School made national headlines for its move to have a closed event where Parker would speak only to Māori and Pasifika male students and their fathers.
On Wednesday there will be a hangi laid down in Majestic Square. The hangi will be eaten at a charity dinner at Frank Bar + Eatery, which Parker will also attend.
Money is being raised for local boxing club Awa Kings and there will be a charity auction.
Parker will also visit the Holden car dealership in the city.
On Thursday morning Parker will be the guest speaker at a Whanganui Māori Business Network breakfast at Parnell's Cafe.
Parker will then go through some firearms training at a local range before being taken to the International Commercial Pilot Academy for a flying lesson.
He'll finish Thursday by visiting the Awa Kings and running a boxing training session.
Parker will spend all of Friday and half of Saturday in the bush hunting pigs, deer and goats.
He'll finish his time in Whanganui with a bit of jet boating.