(1) Single and double strollers are available for rent. Single strollers will put you back $10 (plus, a $5 deposit). Strollers are turquoise with a KBF logo. They are made of plastic and thus I can imagine they are not very comfortable. Plus, the sunshade does a shabby job of protecting baby from the sun's rays and storage space is very minimal (don't expect to store your purse or the baby's diaper bag).
Better Alternative: Bring your own stroller. If you're flying or driving and worried about space, purchase a $10-$20 umbrella stroller when you reach CA. Slather sunscreen on your little one. Bring along a sunhat, sunglasses, and bottled water. You're all set.
(2) Two non-air-conditioned "Baby Stations" are available at Knott's - one is in Camp Snoopy, the other is in the California Marketplace (right outside the park). The stations were dirty, hot, crammed, and uncomfortable. I was extremely disappointed...
The Camp Snoopy station essentially was a small one-room building with approximately 5 metal changing stations, a microwave, a sink, and two "private" nursing areas. The metal changing stations were dirty, uncomfortable, and had a large bar (to protect baby from falling out, I assume...). The nursing areas were off to either side and consisted of an uncomfortable, wooden chair behind a curtain.
The CA Marketplace station was inside the women's bathroom with no signage to indicate that it had a curtained-off area for nursing. Again, the bathroom and the entire area was dirty and unkempt.
Best Bet: Change your baby on your lap in the nursing station to protect him/her from germs. Feed your baby in the nursing station, but don't let baby touch anything (yuck!). Write a letter to KBF management to request better facilities.
(3) Children under 3 are free. Children, ages 3-11, can get in for a discounted rate.
In sum, Knott's Berry Farm is severely lacking in baby amenities. I've heard Disneyland is much better in this category. Post your comments about baby-friendly amusement parks here!