It really depends. He might go back to the cage for toileting but he might also decide it’s too far away. It’s a bit of a gamble. I would opt for a second litter box to save yourself the hassle.

My 8 week old Flemish is free range and not neutered yet because of his age. He has his main living quarters on the bathroom with a bed, and his two litter boxes and food and water and hay and then he has a bed and play things in my living room and a litter box in the dinning room that is attached to the living room that has hay and water there as well and it has worked well for me. Once he is neutered and he is allowed free access to both bedrooms when he no longer marks them then I will have a litter box in my bedroom as well for him. When I first started free range when I got him at 5 weeks I had 2 litter areas in the living room, one in the dinning room, and 2 in the bathroom just so he had plenty of options and then gradually took them away. Only problem I have with him being free range is the marking of my couch when I’m not looking, and the marking on my bed and in my kids room which is all over the floor like 50+ poops and 4-5 pee spots regardless of how many boxes I put in there. So he has limited access to them until he is older my previous rabbit, a lion head would go right to her cage to do her business and eat and such and I never had to add another litter box but she only had access to my bedroom and was free range in there. And she suprisingly never jumped on my bed.

So I would do a trial and error I guess. Add another litter box and if he uses it good, but if he just goes to his cage you still have abox for another room once you give him access to it.