Yup. Even using a camera with the best dynamic range, the floods are going to blow out if you don't compensate. If you compensate (using either EV comp, or just changing the exposure) to reduce the exposure for the floods, everything else will go dark. RAW will help you recover shadow details, but it depends on how far you push them down. The range could be too much and you'll have noise where you pushed it up.
I recommend exposure bracketing. Put the camera into AEB mode set for 5 (not 3) with full 1 stop increments.
The sunset could be tricky as well. If the sun is still up, it's another bright spot that can blow. If you let the sun set beyond the horizon, you will have my favorite kind of sunset sky and no sun to blow out, but now that light is much lower than the flood lights. So once again, AEB.
If you're new to blending AEB shots (they call it HDR these days and as you may have seen, some people overdo it), you might ask them to turn on the floods the night before so you can take some test shots and have something practice with back at the computer.
My favorite HDR workflow is to start in to start in Lightroom, then shell out to HDR Pro in Photoshop, then do the tone grading in ACR (not using the HDR Pro sliders). Let me know if you want the details of this workflow.
Chris