This scenario is quite easy to complete, with plenty of rides, space, and time. A good strategy of building through the park is to use the existing pathways for your guests, but focus on one little area at a time. Example: At the beginning, you should only focus on the first little areas near the entrance. Delete one tile of path leading to the next area and when you want to expand your park to there, refill the footpath.
Be sure to build some transport rides throughout your park, as your park will become very large. Once you get going with your rides, guests will pour in, giving you tons of money. Just keep building lots of roller coasters, and you can't fail.