Although you have very little land area suitable for building rides, you have several good rides available from the start, including the Gravitron and the Whoa Belly. Build one of each of those rides along with a gentle ride and a small roller coaster below the dam on the shallow water body, and then connect the newly built rides to the area above with a path and a Chairlift. Be sure to build an Information Kiosk to keep your guests from getting lost, as your paths may become complicated very early on in this scenario.
As you attract more guests and earn more money, you should continue to expand in the shallow area as much as you can. You will eventually need to build on and in the hills as well as on the lake above the dam, but you should have enough money and ride options available to do so if you plan carefully. Should you still be shy of 1,400 guests toward the end of the final year, use advertising campaigns; do not slash any prices, as doing so may deprive you of money you may need to build one last good roller coaster.