You can download another copy of the letter, to give to the king;
Lost Items - guide and directory of inventory files

The blessing ritual is a one way trip to the final area of the game, so you can not get back by normal means. You can get back by Teleporting Anywhere, via hex editor, but I'm not sure if that would allow you to complete quests, or not (the quest log gets reset after the ritual, which might just be cosmetic, or it might not).