Is this temporary or permanent? Also hard to know without knowing the shape of the area.
200 users at 2Mbps is 400mbps, so depending on the phone type and if they are mostly 5Ghz or 2.4Ghz, I would look at 3-4 AP-277s. Those APs are good for outdoor installs or installs where corrosion will be an issue. That would give you 100Mbps per AP or 50Mpbs per radio, with 50 users per AP. You can likely get away with 3, but again without the ma/floorplan and where the users are sitting, it's really hard to know.