I don't know about out of state guests but just wanted to mention that the "local" DLR area encompasses a huge area with hundreds of school districts, each with their own schedule. While some schools may still be in session next week not all will be. My son's school district is off the next 2 weeks. So, will there be crowds? Yes, it will probably be pretty crowded until the end of April when the last spring breaks happen.
The best advice is to tell your friend that they HAVE to get there before the park opens. This will give them at least an hour or two of shorter lines before everyone else shows up. Also, they will have shorter food lines if they try to eat earlier (11 or 11:30 for lunch, 5-ish for dinner). Hope they have a great time!