I would go back to a little bit of the zoom around the field.chasing the kong stuff. He's 4 mos old now - they grow fast. If he came down with pano, then he'd go on a lot of "bed rest" take it easy stuff. But that aside, BTY2 as a pup was notorious for chewing up crate pads. I purposefully chose 100% cotton, bath matts with no backing. I figured that they had a better chance of passing comfortably and maybe even being somewhat digested. I think ripping them up was entertainment for her. Because I was not working at the time I got her, she wasn't crated for long stretches but she still managed to mangle the mats.
Your son is old enough to be in school for 8 hours a day, and it sounds to me like you and your wife have a pretty good routine worked out. I'd guess your son is involved, too. I'm thinking you are doing pretty fine. I've worked while I had a new pup in the house for four of the five pups I've had. For a few weeks I would race home at noon, let the pup out, put the pup up, go back to work. It worked. It's going to be fine with you, too. (this last one, that I was home with, was probably a bigger issue - ate zippers, ate zippers out of dog beds, ate zipper out of training vest before I ever got to use it.)