Mario Kart: Double Dash!!/Shortcuts

In many tracks there are various shortcuts to take to avoid getting beaten or to set a new time trial record. Below are some:

Luigi Circuit: Shortly past the starting line there is a Chain Chomp (consider it a big, round dog) guarding a path off to the right. If you get a boost off the start line and "mini-turbo" into the shortcut, you should have no trouble getting by him. Executed properly, it'll save you about a second per lap.
Peach Beach: 1) There will be a separate route in the beach area that goes over water. 2) After starting the course there will be a sharp turn. If the player head left instead of right, the player will be sent through a pipe and back the way he/she came (this shortcut is a big time waster and should only be used to get items). 3) When finishing the race, a set of items can be obtained by driving behind the plaza statue, giving generally the team's special item and a blue shell.
Baby Park: The only trick with this course to to pull off extremely tight turns.
Dry Dry Desert: Don't get sucked into the tornado or quick sand pit.
Mushroom Bridge: 1) Halfway through the course will be a hill off to the right. Go up and over it to cut across the track, however, the ground isn't very good to drive on and will take approximately the same amount of time as driving on the road. This effect is removed while under the influence of a mushroom or star. 2) When a player gets to the bridge he/she can go to either the left railing or right railing and use accelerators to boost themselves to the top of the bridge, however, it is very easy to fall off, which would cause a loss of time greater than simply driving on the bridge, so many players avoid the rails. 3) In the very beginning, off to the right is a passage that leads the player in two 90 degree angles and through a warp pipe. It is a time waster but if the player is in 8th usually the player will get good items.
Mushroom City: After going around the first curve, go straight past the fork in the road. Off to the right about 30 feet afterwards, there is a pink(?) alley spliting between two buildings with several boost pads. It will cut a lot of time off your total.
Mario Circuit: No data at this point.
Daisy Cruiser: About 3/4 of the way through the course will be a hole, which leads to an underground chamber. In the chamber is a pipe that will suck the player out and back onto the course. This shortcut will not shave off much time, though it will let you access some good items.
Waluigi Stadium: No data at this point.
Yoshi Circuit: 1) In the beginning there will be a shortcut ramp going over water. You can only go across it by using a mushroom or a star. 2) About halfway through the course will be an underground shortcut below the track and off to the side. If a player wants to use it the player must drive off a cliff and land on the edge of the shortcut (which is only possible with a Golden mushroom or star).
Dino Dino Jungle: 1) After leaving the cave that leads to the bridges you can turn right, there's a alternative bridge with boosters. 2) In the cave part of the course is a ramp going over a cliff. The player can only get across it using a mushroom or a star.
Bowser's Castle: In the part of the course where fireballs are being shot at you there is a hair-pin turn. When done correctly, a player can cut across the turn by going over lava, however, it is very easy to go flying off the other edge of the lower road or simply not make it to that road.
DK Mountain: 1) After being shot up the mountain you enter the grassy section below, after the first full 180 turn you can turn sharply to the right and jump over the abyss (this takes a little practice). 2) Whilst coming down the mountain, driving on the off-road ashy section will not reduce the kart's speed, avoiding the time-losing bumps and getting a better angle for the next turn.