Evergreen Gardens is one of the largest parks in the original RCT, and has one of the largest loan limits of $40,000. The primary problem with this big, beautiful, undeveloped park is its over-developed path system; which covers a good part of the park. When you begin developing the park, you will get a huge load of "Guest # is lost and can't find the park exit." Even if you build one or two Information Kiosks, these guests will still get lost due to the paths. The park is also large enough to where you should consider one or two forms of transportation so the guests can make much of their experience, and their money.
Since this scenario is very large and you probably can't fully develop it in the beginning, it's better to cut off the paths leading to places you can't develop just yet. Wait until you have more guests and more money to spend there, then re-connect the paths back. Even if you have Corkscrew Follies/Loopy Landscapes (hence, 'No Entry' signs), it's better to simply cut the paths off as your staff will ignore the 'No Entry' signs.
In the beginning of the objective, you'll notice you're lacking on all elements that a park needs other than theming. Set research to maximum and include roller coasters, thrill rides, gentle rides, and shops/stalls. You should actually include only shops in the beginning so you can research the Information Kiosk, which is the holy grail of this objective, since the guests will get lost very easily.
You have $40,000 at your hands so you should be able to get a good start on developing the park. Don't go overboard on building rides. One coaster (Woodchip makes for a nice start), all the thrill rides (you only have two...) and a few gentle rides will really attract some guests to get some money rolling in. You shouldn't spend more than $12,000 on all of this. Hire some mechanics and handymen to keep the park in order. Assign small patrol areas. Your employees will wander just like the guests, but you won't get notified about it.
Food, drinks, and bathrooms will be very important in this objective. You should have at least 6 bathrooms, 8 or 9 is recommended, and at least 4 tandems of foods and drinks. Guests will get tired in the park, so place benches everywhere.
Slowly continue to expand the park as new rides become available. When you get the Steel Coaster, you should build the Shuttle Loop (even a twin if you want); this is a very popular ride and will attract a good number of guests and earn you a lot of money. When you start to make near $1,000 a week, you should invest in either a Miniature Railroad or a Monorail (the latter is recommended) to help get your guests to the back end of the park without getting lost or tired. An Observation Tower will help the guests see where they want to go and prevent them from getting lost.
The objective's challenge is handling a large park while still trying to improve it. Don't worry about attracting huge sums of guests at the start. Just get the park functioning and try to bring in some money. Keeping with a good building pace, you should be able to have more than 1,200 guests by Year 4 with no advertisements. 4 years is plenty of time to get 1,000 guests in the park. Just take your time and make sure you satisfy your guests, it will help attract more over time. You'll probably achieve your objective using only half the space, but this park can be completely filled with rides, reaching a park value of $70.000!