- slide 1 of 5
A Trip Across the Plains
Ah, sky. Haven't seen that yet in Hyrule - it can be assumed Kokiri Forest had a lot of overgrowth and let the sun filter through. Anyway, perched on the rock wall just outside Kokiri Forest is a giant owl who introduces himself as Kaepora Gaebora. I thought no one could get more annoying than Navi, but I was wrong. You'll likley wonder why Link hasn't tried to slice her up out of sheer principle.
The owl tells you about Hyrule Castle and how it governs and all sorts of ultimately useless information. One thing to note: time passes in Hyrule Field, and most of the rest of Hyrule. The castle gates close at nightfall (when you hear the wolf howling) so Link's trapped outside until dawn. Odds are, he's not fast enough, even when constantly rolling, to make it from the forest entrance to the gates in the space of a day.
You won't be bored waiting the night - at night, Stalchildren (skeleton-like creatures) pop up out of the ground to attack you. Spend the night killing things, getting Rupees and such. When dawn comes, you can enter the town.
- slide 2 of 5
To Market, To Market
The first building Link comes across is the guardhouse. There are dozens of clay jars inside, with Rupees in them. Apparently Hyrule Castle Guard isn't very organized or competent, or they wouldn't leave such a mess. Make a note of this area - you can come back here to stock up on Rupees if you need to buy something for Link.
Pass through into the main marketplace. There are plenty of people around doing their shopping. Some buildings are here as well, like the Shooting Gallery, the Treasure Chest Game (where you can win a Piece of Heart), the Happy Mask Shop and the entrance to the Castle area itself. Don't bother with the people, they don't tell you anything important. Instead, go talk to the little red-haired girl standing near the fountain. She will introduce herself to Link as Malon, the daughter of Talon, owner of Lon Lon Ranch. Lon Lon Ranch is that plateau structure in the center of Hyrule Field - you'll visit there later.
- slide 4 of 5
Into the Castle
Now, have Link go through the gate, where you'll see a giant plain with Hyrule Castle at the end of it. Be careful, there are guards here who'll throw Link out if they see him. Keep your distance. Malon is standing by the right-hand wall, so go talk to her. She's going to look for her dad, who went to the castle to deliver some milk but hadn't come back yet. What a great father. She'll give you an egg, along with what I think is some of the most innocent-yet-disturbing dialogue in a Zelda game: "I've been incubating this egg very carefully....hee hee!" I mean, come on, Nintendo. Beth wiggling her hips and moaning when Link demonstrates his sword/slingshot skills in Twilight Princess is bad enough, but dear God.
There's a specific route to take. First, climb up the vines near Malon. Run along the wall past the gate and drop down on the other side of it, continuing along this low path. Link will come to a fork in the road. DO NOT take the road, there are guards stationed nearby. Instead, make a trip up the side of the hill to the left. Keep going until you come to a dirt path. You should see the wall directly ahead, with the gate and two guards. Go all the way to the left-hand wall, keeping out of the guards' sight. Next, there'll be a rough patch on the wall to climb. Go up this, jump down and straight ahead into the moat, then swim to the other end and climb out. By this time, the weird egg Malon gave you should have hatched into a Cucco.
- slide 5 of 5
Use the Cucco on the big guy sleeping near the wooden crates. He'll wake up, introduce himself as Talon, Malon's father, then take off faster than you'd expect him to be able to run even in the best of shape. Now, look at the wall on the other side of the moat - there's an open water duct big enough to crawl through. Push the crates into the space, then jump across and through. This has to be done in the daytime, or else the guards of Hyrule Castle will be standing waiting when you make it through.
Now, you have to be very slow and careful. The guards in these various chambers of the Hyrule Castle Courtyard walk plotted routes. I suggest staying well out of sight until you get a feel for their patterns, then run through as quick as you can. In the chamber with the trellis over the two guards, walk slowly over it to keep from falling. If you keep your head in this part, Link will be able to make it into the main castle garden, where Princess Zelda will be waiting.