VisElEchNon: As far as I know, that is the only non-magical way to do so. Sleeping only heals a few HP, if you're lucky, and a lot of times none at all. Potions/spells are much faster.
ashout: so i guess you die a lot in the beggining. almost all the monsters i face are way too tough for me, they kill my whole party in no time.
I guess what you do is, you look for a dungeon to explore, and once you've found a dungeon, you use it to level up, but in the meantime you just explore the city's and talk to people, and when your out in the wild, you avoid encounters with monsters and sleep through the night, praying nothing attacks you?
basically, just a bit of warning if you go to a town and it says their is a air of Hatred, Cowardice or Falsehood there just leave and comeback some other time as a Shadowlord is hanging around and all the townies will be under their infulence so if the shadowlord of falsehood is there the townies will all lie, Cowardice they will all run from you, Hatred they will attack you on sight,
Also that weird blue guy that often shows up when your sleeping is lord british, he will give you a clue to your quest if your karma/vitue is high enough. Also go on replacement docs
http://www.replacementdocs.com/download.php?view.959 and download the record of Lord British's expedition to the underworld(I added a link to the download) it was a piece of fluff that came in the gamebox that tied into the game and also gave you a clue to where one of the items you needed to finsh the game that wasn't included with the version on GOG