Lost In Oz trilogy by Joshua Dudley takes place a few months after the original book left off.
Joshua and his other Oz tourist group are now in the Mifkets Asylum, along with Alice from Wonderland(shades of American McGee's Alice?). Tamara, Tommy, and Laura manage to get back to Oz along with Dorothy via her magic slippers. Once there, they learn that about a century has passed, and Oz has been dominated by a new evil overlord called the Dark Wizard. They ally themselves with a group of fairies lead by the mischevious Pina, who are really working for the Dark Wizard, which Dorothy discovers, but the pixies use some amnesia magic on her to make her forget. Meanwhile, to double his chances of total victory the Dark Wizard has resurrected Bastinda(the Wicked Witch of the West), and plans to find the Great Book of Records to rewrite all the great disasters of Oz into one killstroke. But he also needs to acquire the Candle of Truth in order to do this. Back on Earth, Joshua befriends Wogglebug who was sent to him by Ozma and the remaining Ozians from the original timeline. He warps back to Oz with Toto, and is introduced to Oz's heroes, including Glinda, Tattypoo, Tik-Tok, a resewn Scraps, and the new Good Witch of the West. Tamara and the others are surrounded by the Nome King and his troops, where Tamara learns that she can use dark sorcery to ward off the nome army. Bastinda summons the Jabberwocky from Wonderland to collect Dorothy and Tommy, leaving Laura behind and seemingly dead. Tamara follows them, only to learn that the Dark Wizard is really her father from Earth, who convinces her to use her newfound powers for the side of evil. Ozma informs Joshua that the Dark Wizard plans to kill both him and Tamara so he can gain both of their powers. Joshua leaves to confront Tamara about this, who transports them to the Dark Wizard. Bastinda in the meantime gets the magic slippers from Dorothy, which end up to turning her into ashes. Tamara them reveals that she was only faking being evil to learn the Dark Wizard's plan, and they manage to use the Candle of Truth to send them back to Earth just before they first arrived in Oz. Alive and well, things seem okay, but a whole bunch of tornados show up like they did at the beginning of the first book.
This book had a little more of an original adventure than the first one, and not just an alternate walkthrough of The Wizard Of Oz. Although there's a few things that were left out, like how realms like Wonderland are connected, plus the regular characters(both original and from Oz)don't seem to have room to develop very much. It's like we're introduced to Gloma(the new Witch of the West)but given no backstory on her, plus one of the original four characters from the first book just gets killed off because she didn't have much anything else to do in the story. Anyway, if the first volume peaked your interest, then you'll probably dig this one too. This leads into the upcoming third and final book, Temple Of The Deadly Desert. Plans are also in the works to do a Lost In Oz comic series too.