Eventually the subject of where witches get their powers is going to come up. When it does we often have to deal with the Underworld and who lives there.
It gets called a lot of things, The Ever After (Rachel Morgan), the Never Never (Dresden Files), the Nether Realms (Buffy in one episode), Hell, The Abyss, the Pit. I have to admit one of my favorites was from the Beetlejuice cartoon, the Neither World.
In my games I typically say witches can't be raised from the dead since they reincarnate. So if you want to get someone back from the underworld, you are going to have to go there and get them.
This is not an uncommon approach. The Descent into the Underworld is a very common theme in many myths and stories. We see it in Orpheus, in Dante's Inferno and it is featured in a number of games.
I even ran a game where the sole (hehehe) purpose was to retrieve the soul of a loved one and bring them back. It was a playtest for Ghosts of Albion using the Army of Darkness rules. Since it was around 2002-2003 there was only one logical choice, Xena. A group of adventurers had to a get Xena's soul because Xena was the only able to help them. But to that they first needed to find Gabrielle. The adventure's name ("A Friend in Deed") was even a play on the name of the final episode of Xena ("A Friend in Need"). The double play on words here is the last episode was "FiN" and mine is "FinD".
This game also gave me the idea to write my d20 ritual spell "Descent of the Goddess" as spell a witch can cast on someone so they can go down to the underworld and plead their case to Death. Yes. If you look behind you before you leave you will loose them forever.
I did not do a Descent into the Underworld when I brought back Tara in my games. I thought the big adventure to get someone was great for Xena, but for Tara that is not how I wanted her return to start. I just had her show up one day in the episode "Will We Burn in Heaven?"
Of course the Descent doesn't always have to be bad. Rachel is in the Ever After every weekend. Dresden pops over tot he Never Never all the time. In games it is often a matter of finding the right gate or spell.
For Ghosts of Albion I have always wanted to use a ghostly train.
But I still like the idea that you need a witch to help get you there.