Ok so I found this out a while ago and I posted it on another site but I just realized that I never posted it on MMOwned so here it goes:
Say you just finished doing any instance that can be made into a heroic and you want to hearth but dont want to use your hearthstone, all you have to do is walk out, reset all instances, enter the instance, change to heroic while you are in the instance, log out, then log back in and you should be at your hearth spot.
don't flame me if this does not work anymore, im at school and cant test so if it doesn't work then I am sorry and a mod can just lock the post. If it does work then have fun
p.s. this is a lot easier than the whole enter an instance, invite a random person, leave party, + wait 1 min.