parrotpie

If you really want to grind sneak, and it not at all effective until about 90, the go back into the room where Sellous Gravious (the chargen guy) is. Stand in a corner by the door and wait until he and the guard are not looking at you then hold down the sneak key with a weight and go do something more interesting. After about 8 hours your sneak should be about 100.

TES is not 'required' to play with or without mods. It has only one function to create oe alter mods. So unless you plan to make mods, alter mods to your liking or correct the errors that are in some mods then you do noy need TES. If you want to do any of these you could look at openmw, Their editor replaces TES.