This scenario is actually quite easy if you know what needs to be done. Crumbly Woods has the highest guest count demand of all scenarios in the original RCT, tied with Mel's World, but it already begins with 600 guests. Thus, you need only to attract 600 more guests over the next three years.
The main problem in Crumbly Woods is that the rides are outdated, unreliable, and not especially profitable. You have three options for addressing this: you can demolish the old rides and start from scratch, persevere with the old rides and build new rides in the remaining space, or rebuild all or most of the rides in their original place and add more attractions as you can. The first and third options are both reasonable, whereas the second should only be attempted as a challenge.
There are advantages and disadvantages to each choice. Demolishing all of the rides from the start will earn you a sizeable lump sum but leave guests unhappy in the short term, cut off your primary revenue stream, and leave your park with a mess of empty paths and aimlessly wandering people. Retaining the old rides in the park will only lead them to deteriorate further and make less money; Double Trouble may even experience a station brakes failure crash.
First, you should pause the game. If you wish to place a gate fee, you may do so, but charge no more than $10.00 and adjust ride prices accordingly. Change your research funding from minimum to maximum, and direct your priorities to thrill rides; once the Launched Freefall and Top Spin have been researched, switch priorities to whatever you wish but preferably to roller coasters. That done, hire more handymen and mechanics.
If you are going to rebuild the rides, save the track designs of the two smaller roller coasters; Whiplash can be saved trouble-free, but Mean Squeak will require its underground sections to be demolished first. This will not work with Double Trouble, however, as its underground sections are too large; while you develop a plan for it, reduce its vehicle load to two maximum length trains to prevent crashes and reduce its inspection interval to 10 minutes to reduce down time.
Close Crazy Critters and remove its queue path; you may wish to keep the ride standing until you decide what to build in its place, but you should eventually demolish it since it is too long. Following that, build benches and litter bins throughout the park. Rebuild the gentle rides if you wish, but consider relocating their new counterparts to make more efficient use of the little flat space available in doing so. Renew the other roller coasters by using the track designs you saved. Last, reconstruct Double Trouble piece-by-piece or demolish it entirely. You should rebuild the coaster exactly as it was, as you may charge an admission as high as $8.00 if no gate fee is in place since it has an excitement rating above 8 and the guests in this park are able and willing to pay $8.00 for a roller coaster ride.
Construct some other rides, preferably roller coasters and thrill rides, throughout the park to attract more visitors. Build another path through the park to connect the entrance area with the fantasy land to prevent guests from getting lost, and redevelop the fantasy land by adding new rides. You may even choose to build a newer, shorter version of Crazy Critters to stay true to the original park, but you may prefer to build a roller coaster and some smaller attractions instead.
You should not need many new rides to achieve your goal, but you should still squeeze in what you research. If the end of the scenario is near and you need more guests, do not be afraid to advertise. Every attraction in the original RCT is available in this park, so feel free to experiment to see what you and your guests like.