Crowds shouldn't be too bad.You will get to do everything with the Express pass.HOWEVER, If Harry Potter is on your to do list , you will want to utilize the 1 hour early opening for resort guests ( it is only for Harry Potter).Forbidden journey and Ollivanders are not on the Express pass, and waits later in the morning/afternoon can be an hour or more( even in the less crowded times).Also, Rip Ride Rocket coaster at Universal studios ( it is the ride people generally head to first at US)and Pteranodon flyers at IOA( kiddie ride) do not take the Express pass.Hard rock pool is popular, and since Universal resort guests CAN pool hop, it can be a busy pool.Club level crowds depends on simply how booked the club level is that time frame.Meal times and first thing before park opning, club lounges tend to be busier.Lunchtimes are not bad and in the evening it can be busy again..All depends on how booked the club level is for that timeframe
My wife and I will be going to Universal first week of March. Mon March 5th-Thursday March 8th. My questions are how crowded will the parks be? We will be staying at the Hard Rock Hotel, so we will have FOTL passes. Will we be able to do EVERYTHING? We will also be staying on the club level, will this be crowded durring breakfast, and evening snacks? Last question now, I promise. 
Should we expect the pool to be crowded? Thank you all in advance! This is our first time, and we are very, very, excited!!!
