None whatsoever. All that is needed for Brookwood Gardens is RCT2. However, the park will not be available for download right away. Instead, the individual coasters will be released over the course of 2016 into Build It rounds.

@Terry Inferno, how many roller coasters you talking? I have been working in TCP (Track Creator Park) on numerous rides, when I am finished, all of said roller coasters will be put it a different park and will have screen-shots taken of it. (To remove the plain looking landscapes).
Some will be entered into Build It!, others will not. It's just a matter of which I think COULD win and which couldn't. As of now, I have two different possible Build It! entries. That number could most definitely increase. However, there aren't going to be screen-shots or posts about them as it is against the rules; as stated by Justin. I am mundo pumped for Brookwood Gardens mate! Also, just a note, it does make me happy that there will not be any add-on packs. I wish'd I had RCT2 TTP, but alas, I do not. Which, in a sense helps me too, I have ran into nun-ta-million scenarios/rides, ect... that you need add-on packs that makes me unhappy when I don't have it. Currently, that is why ALL of my creations need JUST RCT2. In the future, I will get RCT2 TTP for special purposes, as well NL1 & 2, RCT3 Platinum, and RCTW. Then, I can enter other stuff than just RCT2.