Crate tips
I agree with many of the tips above. I am new to owing a cocker, just got Gizmo march 8th, he was already 14 weeks old. He couldnt stand his crate at first, he still isn't a fan of it and would rather sleep on the floor. However since he had to be housetrained I and he didn't have a choice.
I tried the treats and all and he didnt work. So I actually stuck my head in there and laid him next to me petting his back and saying good boy for like five minutes and it helped. I also had a night light nearby for the first few nights so he could clearly see me. I think one of the best things I did was changing his bed to a more comfortable one. I took him to petsmart with me to pick it out, I let him sit in it and his new car kennel on the way home. So he was used to the bed and liked it in his crate. PLUS, I take him with me when I visit family and what not, and in the car he is in a plastic kennel. So he gets used to being locked up and resting during car rides, so it made his home crate more relaxing.
Gizmo is now 17 weeks and doesn't mind being in his crate. he lets me put him in with no problem, and he gets in the car kennel all by himself. No more night time whining. Now I usually hear nothing from him until 5:30-6:30 am when he is ready to go potty. lol.