Rainbow Valley is probably the hardest scenario in the original game, with Mystic Mountain as a close opponent. The objective is simple, and the same as Evergreen Gardens or Pacific Pyramids, so, at this point of the game, getting 1,000 guests in 4 years should not be a problem. The main and great difficulty here is the actual terrain, as tree (or major scenery objects eventually placed) removal is plainly forbidden, as long as land or water adjustment. This scenario is similar to Harmonic Hills in the Corkscrew Follies expansion, though Rainbow Valley should be way less difficult. The key here is for players to take advantage of rock vertical faces that are exposed throughout the valley extension (as underground building is still allowed) to build underground roller coasters and tracked rides, and therefore save vital space overground. Players should only add scenery if they're confident in it not disruptive for future construction ; once scenery is placed, it cannot be taken off. The terrain is quite hilly and very little available flat land will be available besides the narrow river. Because of that and the main aspect of this scenario, it wouldn't be a surprise if pathways and even track layouts get a little clumsy and inconvenient, but it's very important for players to do their best to keep a good infrastructure : if guests get lost, they will want never to come back.
Research set at maximum funding at March 1st Year 1, will be complete by October, Year 4. That means the player will have everything the research can offer in this park. At the beginning, a decent amount of good coasters are available, especially the Steel Mini and the Wooden Crazy Rodent which are excellent to start off with, as they are very cheap and compact, making building around the trees and terrain much easier. The only alternative is the Shuttle Coaster, which might be needed at start as always for quick money leverage.
Roller coasters should be built taller than trees of course, bringing them to ground level only at the station. Another thing to note is that even if a ride fits somewhere, the pathway to it may not. Therefore, players in RCT1 should check for pathway room immediately before building a roller coaster, and do so very carefully. Players in RCT2/OpenRCT2 can shift the initial rail up, allowing them to escape this task.
Attracting 1,000 guests over the 4 years of the scenario is not difficult by itself — the real challenge is constructing the park. Players must think their rides designs ahead of time and, if for safety, save their game before building any large attraction. The park doesn't seem big but it's pretty larger than necessary. By building the park up and attract guests slowly and methodically, players will eventually succeed without having to resort to marketing campaigns.
Rainbow Valley — completed by Zachl1226.
Rainbow Valley — completed by Felipe717.
Rainbow Valley — completed by Hadesengel.