I've trained puppies with and without crates, and I'll never use a crate or barricade again.
Dogs instinctively like to curl up in small enclosed places, like a crate, which makes crate-training relatively easy. Downside is that the crate becomes the security zone for the dog, and that's where he'll go in an emergency or when stressed.
Instead, try socializing your puppy with you and your family so that you become his security zone, and by your side is where he feels safest. While he's too young to trust, you'll need to confine his movements a bit, which you can do with a short leash attached to something near you, where he can always hear and smell you, and you can touch him frequently and talk to him.
Think about your apartment and your working/living habits at home. There is probably a radiator or a heavy piece of furniture near your usual haunts that you can use to attach a short leash. You'll need to remove rugs for a few weeks, and if you have carpets, you'll need to plan some way to protect them.
I got this advice from Paul Loeb, a trainer in New York who works with pets in film, theater, and advertising. I see one of his books on dog training, "Smarter Than You Think" is still in print in the US - it's highly recommended (and totally unconventional). Following this method, my current dog - a super-alpha male West Highland White Terrier - adjusted to home life almost immediately. He was house-broken within a couple of weeks, and has been a loyal member of the family now for 15 happy years.
