Thread:Sinthorion/@comment-25359794-20151016165446/@comment-25612015-20151017142300

If you want players to spawn directly in the Middle-earth dimension, that will be the default in the next beta of the mod.

If you don't want to wait and are using a Bukkit/Spigot/(K)Cauldron server, you can use the Multiverse Core plugin to teleport players across dimensions (this is what I use). I also used the ServerSigns plugin to allow players to activate these cross-dimensions teleportation commands from a sign.

Or you could also arrange for the ring portal to be located at the spawn point in the Overworld, maybe in a hole so that the players can't get out of the ring portal...

However, I have no experience at all with spawnTP.