-Geoff

First off sleeping can be gotten around you mentioned speeding up time during that period, but there are alternatives for one sleeping doesn't really help heal barely at all and is only used as a method of going offline, two meditation is used rather than sleep player is fully rested in about 30 minutes but player can wake up at any time or can rest in short segments like 5 mins or so this way if hes not watching and monsters stumble upon him hes fried but if watching he can wake up immediately and react to there appearance, three sleeping can only be done in inns or waystations etc... and if it takes no game time it doesn't matter because you are in a safe place and there are no important changes in the surroundings that would need made, four AI areas can be set as circles including all Items nearest any given player and players can only sleep if the AI areas are above a certain size so instant AI computation for an area can be derived semi randomly for instant completion and only time of day will stay the same, this way it won't noticably affect other players and creature placements and other changes will be made in areas affecting player, five I don't know can't think of any others off the top of my head, but they are out there.
Now about travel, this is harder. Teleportation obviously works but is impractical as only method, possibly again using AI spheres you could have player automatically move from area to area going out of auto whenever they get to near another AI or Player that way speed would be possible but in areas near possible conflict they would accually be able to see the enemies before hitting them unlike the common instant travel encounters and all groups on a road would pass as they went so theyb would have better player interaction for multiplayer, three make caravan and boat trips possible for money and have them move your char over areas without you being there in large multiplayer it would mean your char might not be there for an hour or so, but that can be done while offline, in single player it could be a safe instant travel mathod, sorry can't think of four right now.