Toontown has always opened 1 hour after regular park opening. Well maybe not always but for years anyway.
They do a rope drop for it. A couple characters, Minnie and Goofy seem common, will come out and chat with the kids a few minutes prior. Then when the land opens they will escort them into the land.
There will be a sign at the entrance, just before the tunnel, stating what time the land will be closing. It will not reopen. Oh and closing really does mean closing. So if it says closing at 8:30, they will shut down ride lines earlier to get guests through and outta the land not much after the posted time.