You will need to follow the directions to get out of the raid instance, I will show step by step screenshots, showing you how to leave the raid instance, and get into the actual world. Many of these area's are cut off, and NPC's are not loaded. But, you can explore many zones, including an area that looks like the premade version of Tanaan. It's a great way to see some of Blizzard's artwork, before they finished the zones. There are quite a few screenshots, so brace yourself.
https://i.imgur.com/Qdem1Fc.jpg
https://i.imgur.com/fBUtBpb.jpg
https://i.imgur.com/LeDBcuU.jpg
https://i.imgur.com/5Ln6KYn.jpg
https://i.imgur.com/ti2quVj.jpg
https://i.imgur.com/EHaSieQ.jpg
https://i.imgur.com/X7VmLa5.jpg
https://i.imgur.com/z931MEm.jpg
https://i.imgur.com/nJTXh5I.jpg
https://i.imgur.com/q6k5lfA.jpg
https://i.imgur.com/EBaP63k.jpg
https://i.imgur.com/B5xiT7I.jpg
https://i.imgur.com/UXihpDK.jpg
https://i.imgur.com/iNWJ4zq.jpg
If you followed all of the screenshotted steps, you should be able to jump down. Be careful of falls, and have the water walking mount ready. If you explore to the right, and get past Brackenspore's area, and go onto the island in the background you can see while killing him, you can explore many zones that were made by Blizzard.