Depends on what day you go as well. While it might be a little bit busy with spring breakers, the weekdays are usually pretty nice crowd wise. The first couple of weeks of April often tend to get more Spring Breakers than the last couple of March.
Oklahoma, which is often the biggest Spring Break crowds, is actually on their breaks opening week or the week before (checked Norman Tulsa, OK city and a few others). So they won't impact SDC's calendar in March at all this year. Most of the Arkansas Schools seem to be on break the week of the 20-24, but they don't seem to bring as huge an influx of attendance as OK does.
The biggest things you'll find is a few of the restaurants and several of the stores (especially the leased ones) that won't be open in March and April. And the entertainment choices are pretty light until the festivals kick off.
You may also find some slow operations/ services, especially the first week, as employees are learning their jobs and getting back into the swing of things. Opening weekend is a weekend to avoid for that reason, as well as it typically getting swamped with crowds excited to go again.
But I always enjoyed working with the lighter crowds during the week for the first 2-3 weeks. Allowed you a nice easy way to work back into things and get to know a lot of the guests that are visiting.