after you have got the rainbow wing (after suicune) you can get mtfaraway and ho-oh
to unlock the fields get surf in solar cave after the fields u get mt.faraway
Lots and lots this should help: http://www.serebii.net/mysteriousdungeon/dungeon/22.shtml
get past lightning field, fiery field and northwind field and then you get there PS cant recruit ho-oh on first try, almost 100% chance you will on 2nd
There are 40 total floors on Mt. Faraway. More Details: At the top, there should be Ho-oh, unless it has already joined your team. On the 30th floor of Mt.Faraway, there is a friend bow item behind a locked door and you need a key to unlock it.