Venus Ponds/Scenario Guide
This one is far harder than it looks, since you are facing two difficulty handicaps. Also, the guests are quite poor, averaging $60 in their pockets. Having 4 years to complete this both a blessing, and a curse, since some rides will out-date in this span of time. On the bright side, you have plenty of land to expand.
Keep researching and building rides throughout the whole 4 years. You will need at least 30 rides to succeed and one of them should be a really good roller coaster. Also, make heavy use of marketing campaigns and keep ride fees as low as possible since your guests won't have too much money available.
It can happen that your park will stall after a while, the queues are empty, your park rating slowly decreases, and few new guests will arrive. This usually happens when the first few guests are broke and start to get unhappy. A good measure to counter this is to close all your rides and your park, within some minutes, few hundred guests will have left your park. You can prepare and optimize this mass exit by placing one-way signs, but it should be enough if roughly half your guests leave. This is a good thing, since new guests with full pockets will arrive then soon. Re-open your gates and invest your new money in marketing to keep the guests coming.