Will they make their way up the ramp? I don't know what it looks like but at 4 weeks it pretty much depends on whether they want to or not. I've seen 2 week old chicks easily fly over 3 feet and they could have gone a lot more if they wanted to. So if yours want to be in the coop they will get there, whether they walk up the ramp or just fly up. They are more likely to fly down that walk down based on what I've seen. Mine often walk up.
I move chicks 5 weeks old to my grow out coop a coupe of times a year. It's elevated about 2 feet off the ground. I used to keep them in the coop section only for a week or more before letting them into the run, but they were pretty consistent in trying to go to sleep under the pop door on the ground, not in the coop. I wind up going down there at dark and physically move them into the coop for the night. I have had some broods go into the coop the next night on their own at dark, I've had some that took me putting them in there every night for three weeks before the last went in. I typically have about 20 chicks in each brood. What often happens is that two or three days after I start putting them in at dark a few go in. That slowly increases until maybe a week to 10 days after I start the last are going in. Each brood is different though.
I don't know what will happen to yours if you lock them in for a week. Some of that will depend on the personalities of your individual chicks. Some may depend on what your coop, ramp, and run look like. It can be a bit frustrating at times but with patience you can manage.
