Those light-up depressions in the floor are actually elevator call buttons.
Stand in one (we picked the one on the right, but we're also pretty sure it doesn't matter) and a cage-like elevator will descend on a chain. Climb in and ride the elevator up.
Head to the left side of the large staircase you see at the top. You can balance along the handrail and make your way over the the stairs. At the top, turn right and keep making your way up. When rubble blocks your way, keep climbing up.
At the top of the rubble, you'll find more ivy to climb. Climb all the way to the right and up, then follow the path back to the left. You'll find a chain at the other end. Climb this as well. Follow the wooden walkway at the top to another patch of ivy to climb.
At the top of this one, there's a stone arch that you can walk across. At the other end, you'll find Trico's tail dangling down. Hop on and start climbing. You won't be able to go all the way up, though. About halfway up, hop off onto yet another ivy patch on the wall. Crawl along the ivy to the left to find a log you can jump onto.
But that's not Trico!
Continue across the log and jump onto the ivy-covered tree. Climb to the top and jump onto the rope stretching off to the right. At the other end, jump onto another ivy patch on the wall and follow it to the left.
Hop to the wooden ledge you find there and then onto more ivy farther to the left. Take this patch as far as you can, then drop into the nook you find. Even farther to the left, you'll find a tunnel you can crawl into.
On the other end of the tunnel and crevice, there are some pillars on your right you can climb up. Then, climb onto the, you guess it, ivy and take that up. Turn left at the top and run over to the ladder.
Take the ladder down, then take the next ladder as well. This one doesn't go all the way to the ground, so you have to drop the rest of the way.
Climb up onto the rubble in the back left corner right by where you dropped in. Climb up onto the next two platforms.
You can't quite jump to the next pillar from here, but luckily the tricopath jams her head through the wall. Use her head to jump to the next pillar, then wait. She'll do it again and you can continue along to the platform at the end. Go through the crack in the wall and hop onto the chain.
Climb the chain to the top and walk along the beam back toward the wall. Use the ledge to work your way around to a window you can climb through.
Go through the second door on the left to find another elevator cage. Take the elevator up and away from the evil trico. This doesn't go well for you.
The tricopath will get called away. Your job is roll around in your cage until you get tired and then wait overnight. Trico will dig through the roof and find you, but he can't get you out of the cage either.
Hamster ball yourself over the the left, near where the tricopath was laying earlier, where you'll get caught on a curb. Call Trico to push you over the curb and onto the stones.
Keep hamstering along back the way you came. Mostly, you're just going to keep rolling and crashing in a generally downward direction.
Turn left when you get to the landing at the top of the stairs, then continue crashing. Your momentum will carry you across the gap, then you'll land near those elevator call buttons back where you started.
Roll the cage into one of the depressions and it will spring open. But Trico's out of juice again and you need to go find a barrel for him.
You may have noticed a suit of armor helmet rattling around in the cage you rolled down in. This, it turns out, is the key to this puzzle. Retrieve the helmet and carry it to the other elevator — the one that's not broken. Take the elevator down to the room below. Carry the helmet over to the helmetless suit of armor. It will fly out of your hands and activate the suit.
There is a barrel in the alcove where the suit was. Lead it away, then come back for the barrel. Carry the barrel, leading the suit away whenever you have to, back to the elevator and return to Trico.
After he's fed and mobile again, climb on Trico's back and he'll carry you back up. When he gets back to where you met the tricopath, point him up to the hole he came in through.
Once back outside, keep asking Trico to jump. Turn left when you can and let Trico carry you out to the cliff edge.