Thanks for the response, GarthRyan! 
 
I have 2 Barred Rocks, 3 Black Sex Links and 1 Red Sex Link.  The Red SL started laying last week (1 week shy of 5 months old).  Her first egg was laid from the the roost and fell a long way.  It cracked but it was still good, because the membrane was intact and none of the chickens bothered it.  The next day, she laid on the ground, in the run 
 
 
 
I was determined to train her to lay where I want, so the next day, I kept them in the coop until she laid her egg and stayed out there with them, putting her in the nest box a couple of times and petting her until she got comfortable and started making a nest.  She laid her egg in the nest, but the next day was still trying to get out to go lay in the yard somewhere, so I had to stay out there with them and put her in the nest box a couple of time again.  She did end up laying in the box.
 
I decided to take the golf ball out of that nest and leave the egg in there this time.  I was wary of leaving an egg, because it might get broken and I don't want them to ever have the opportunity to eat one and like it, but her eggs are perfectly formed, with very hard shells, so I decided to risk it.  I also added a wider perch in front of the nest boxes to make it easier for them to get up there, because a couple of the other chickens were curious about what she was doing and having a hard time getting up there to watch and check out the boxes. 
 
Yesterday was day 5 and I was gone all day, so I had my husband let them have use of the run, but not let them free-range.  When I got home, she had laid her egg in the nest box beside the one with the egg still in it LOL 

  Funny thing was, the egg left in the box and the golf ball in the other nest, had both been pushed to the edge of the box and her new egg was in the middle 

  I think she's trained now and I hope the others follow suit.  A couple of them are getting semi-close to ready.  Never pictured myself training chickens where to sleep and where to lay their eggs LOL 
 
 
She is laying every 25 to 26 hours, just as someone told me, so I have another question now...  What happens when the time incrementally moves into the night?  Will she lay again from the roost, or wake up and go to the nest box??  Is that why they start sleeping in the nest box sometimes, which I know I don't want.
 
I kinda hate it that they are all getting ready to start laying, just in time for them to stop for the winter molt LOL 

  Oh well...such is the chicken life.
 
Thanks for all the input, everyone!!