There are 4 possible locations where Skyrider can be found. This is generated at random every game. After accepting the quest from Waldo, you can talk to random civilians in C13 and eventually one of them will say something about a swamphouse in a particular location. This give you an easier time to find Skyrider. If the civilian said South West, then it will be in D12, South East means E14, directly East means in C16, and North East means B15.