Here are some good free WoW leveling guides: Been using it for a while now and you could find it is good for casual leveling as well as WoW powerleveling. The guide starts at around 20, but that's cause getting to 20 basically means finishing all starting area quests for each race anyway.

He has nice 1-2 hour long XP circuits in all the major leveling zones like arathi, Stranglethorn, hillsbrad etc and makes good optimal use of walking time. Here you can buy wow gold. Plus it's set up, therefore your quest turn-ins generally happen in large chunks meaning lots of XP all at once (FTW). He makes good use of those "go speak to X in Y zone" quests when jumping from area to area too, just to get that extra bit of XP and unlock a few quests along the way. The guide is updated for all the recent leveling nerfs up to level 60). The outland guides aren't renewed for XP nerfs yet and the Northrend guides are still in progress.

Since you are a casual player, you could be on rested xp for a lot of the guide, and you could find you keep a level ahead of it. If you weren't rested, you'd expect to be right on the guide or within a 5-10 minute grind of the appropriate level.