I have the Gold Pass, which is season passes for both HP and DW. DW is strictly for the 8 (or so) and under lot. No big coasters. Thus, it is never really packed. It gets some lines on weekends in summer, but nothing horrible. The Duke's Lagoon water slides and water area can get crowded on the warmer weekend days. DW is compact, some shade, free parking, and just an overall relaxed, great time for the kids.
HP is a full-fledged theme park these days. I sometime forget that, as I grew up going there. I remember going before the Super Dooper Looper was around. It was a locals stomping ground then. Well, now it is indeed a crowded place. Not much shade at all. Hills to walk, and pretty spread out. Anytime school is out of session, the crowds are there. Use the free preview on the night before you use your tickets, 2 free hours of the least used times oin teh coasters, Then get up early and be there for opening the next day ...