Disneyland is typically open 8:00 am to Midnight during the summer and around all federal holidays. Slow season usually occurs from mid-January to mid-March. Crowds are usually lighter but hours will be shorter and more rides will be closed for refurbishments. On an average day, crowds are lighter first thing in the morning and tend to get busier as the day goes on. The park typically gets the busiest in the evening from around 4-8 pm.
Disneyland does have 3 hotels on property, but will average $250-$1,500 a night. There are a lot of nearby hotels within walking distance or with shuttles. You can purchase your tickets at ticket booths just outside the gate, or you can purchase your tickets in advance through the Disneyland website.