Radish Woods is in the northwest area of the map, just east of an area you can't visit quite yet because of some Dark Mist. Like the one before it, this stage is guarded by another of the statues that wants you to meet a certain criteria before you can pass. He tells you to grab all the money in the world. You can drill the four stone columns in the area for some coins. You need to collect 666 coins. Just worry about the last three digits of your cash supply. In other words, the amount of money you hold must end with '666' as the final three digits (eww, creepy!). The easiest way to accomplish that is probably to buy cakes and such back at Tiese Town until your score is near, then break pots in Monster Village to take care of the last few digits. Of course, the coins that you get from breaking stone columns in the area can help with that, too, but save when you get close to your goal so that if you accidentally go over it you can reset and try again. When you collect the correct amount and talk to the statue, it will let you pass through. Alternatively, you can talk to him a few times and then pay 5000 coins to pass through without the hassle, if you're rich. Regardless of how you do it, pass through and into the next section of the level.
When you enter, you'll see a Phantom ahead, chasing around three acorn-shaped enemies of purplish hue. Head forward and you'll find that you have to jump down a short wall and then run forward and up another ledge to get within range. Do so and use a Spin Drill to take out the smaller guys, then use a drill charge to remove the Phantom's armor. Defeat him, then turn around toward the ledge you descended. There are some pots at the base, as well as a weak wall you can drill for some coins. That will also allow you to climb back up to the top area if you wish.
Now head back to where you defeated the flirtatious Phantom and his acorn buddies and continue forward. Climb up a short staircase and step on the glowing tile with red markings that you find there. You'll cause some crates to appear, off to your left. Drop down and then walk over to them before hopping up them to the raise ledge. Now drag the topmost crate over to the nearby switch, which will cause some wooden stakes to lower so you can proceed along a forest path. This is a dead end, but there are two living trees you must kill and a lever you can pull. Do so. This will open a gate elsewhere in the stage and also cause some new enemies to appear down below.
Head back through the level toward the ledge you stood on when you caused the crates to appear by stepping on the trigger. Defeat the enemies there with a few quick Drill Tornado attacks. Continue past them and up a short staircase. Ahead, you'll note some of the acorn-shaped enemies. They're asleep. Jump forward and attack like crazy. Break the nearby pots and then head left, where more acorn enemies will drop to attack. Beat them and there's a mound where you can recharge your drill if needed. Continue along the path now and it wraps to the right and into a fenced area with a bridge and some trees. There are four vases along the nearby bridge, and you can look left to see a pacing Phantom.
When you head on over and take him out, more Phantoms will also drop from the trees. Here, you want to back slowly away so that the enemies follow you. Then take them out with drill attacks when you're safely away from the water. The last thing you want to do is accidentally knock them in the liquid, where they'll remain alive but more difficult to kill. Once you've taken out all three, stop to drill the wall behind the waterfall and reveal a lever. Pull it to open a nearby gate leading into the next area. Now go break the vases and pots that rest along the bridge's corners before proceeding through the opening and into the next area.
In this clearing you'll find four of the piranha plant enemies. Take care of them and recharge your drill on the mound if needed. Continue along the path beyond them and you'll find another clearing, this one with electrical waves and Phantoms dancing throughout. There are also pots to destroy to your left and a pig-shaped one to the right with lots of coins. Note that you can drill one side of any electrical barrier to disable it. Do so now, then defeat the Phantoms that are unleashed with the usual drill attacks. That leaves one more set of electric barriers, so repeat the process there (and on the Phantom as well) before proceeding and destroying the purple vases beyond.
From the vases, continue along the path as it curves again to the right. When you step into the clearing, walls will go up and you're alone to battle a large, armored Phantom. Drill off his armor first, then keep slashing him back with regular drill swipes and launches. He should fall pretty easily and leave you to destroy vases. With the Phantom gone, you can also continue along the path. You'll have to drop down an opening ahead of a place where branches interlock to block the way. At the bottom, there's a container you can break open to acquire some pieces of Junk. Make sure that you do so, then continue along the underground passage. You'll come out in a clearing where you can destroy some vases and then proceed a black area and into the next portion of forest.
You've reached the treasure room already. Jump up on the altar to grab the GOLDFISH item. Now you can return to the world map and back to Monster Village. The goldfish you found belongs to Rocko. Its name is Goldon. Now more of the Dark Mist will recede from the map. It won't open up any new dungeons or anything, but it's nice to see just the same. Now it's time to head to Tumultuous Cave in Spinach Caverns.