Seattle to Olympic Nat

Hello! Mom and 21 year old daughter Midwesterners planning a 4 day trip in May to Seattle and ferry to ONP- should we rent a car at hotel and drive to downtown- or take rail to downtown and get a rental near Pike area? Also best 2 days to spend least amount of driving and lowest elevation in ONP. Interested in Hoh and Lake crescent I think. Scared of two lane mountain drive. Most central spots in the park to stay? 🙏