Solution based on the one you can find here, proposed by by R.M. Smedley:
http://www.vic20listings.freeolamail.com/vic20/mags/victape/11/Treasure%20Island-sol.txt
I resumed the repeating action by using (xY) in order to make the solution shorter.
go north (x5)
go east
kill troll
go east
climb hill
get item [rope]
go west (x2)
go south (x2)
go west (x5)
climb mountain
get item [key]
go east
go south
go east (x8)
open wardrobe,
go east (x2)
get item [matches]
go west
light matches
get item [cannon]
go west (x5)
go north (x3)
board boat
go north (x2)
go west (x2)
go north
fire cannon
go north (x2)
read sign
go west
read paper
go west
go north
get item [bone]
go east (x3)
throw bone
go north
move statue
