NOTE: These directions may not be exact, but they will get you on the right track.
Answer…
To get up to Melgorhen's Reach…
climb platform
turn wheel
down
out
go bridge
east
east
east
go slope
west
arrange runes (when e is under z, push z; when e is under r, push s; when e is under o, push r; when e is under s, push o. Just keep doing this pattern until you see that all the stairs are in place.)
Go stair
west
close dam
wait for cab to arrive
open dam
go cab
wait till cab comes to a halt
out
go fog
climb vine
go opening
lay on the altar
go shaft
go open
lie down
to get out of the water slide, lean left on the first, third, fifth and seventh turns.