Next question would be how much layer-related stuff do I need to put in the tractor? Still put a couple roosts for daytime naps, I'm assuming? And 2-3 nesting boxes in case they decide to lay while they are out there during the day? Dustbath, toys, 2x food, 2x water... I was also planning on having food and water in the coop, we were just not planning on making the tractor like fort knox since it would be primarily for daytime use. It just feels like a lot, like setting up a whole second coop basically, vs. it looks like most cases people are using the tractors for meat birds with just food and water. And then the logistics of moving them into it each day.
Tractor for laying hens:
Nests, yes. Hens lay eggs at all times of the day. I suggest a few plastic bins that have a lip on their edges, drop them in between two roosts so they hang there, and put a handful of bedding inside. Fake eggs optional.
Roosts, yes. Just put a few suitable boards running across the tractor from one side to the other. Space two of them so you can drop in the plastic bins for nestboxes.
Dustbath, don't waste your time setting it up. The chickens will create one on whatever ground the tractor sits on.
Food and water, yes. You can hang a plastic milk jug by its handle, cut out the other half of the top part, and use it as a feeder or waterer. One in each corner makes 4, which makes two for feed and two for water. Or you can use one bigger waterer right in the middle of the tractor so they can access it from different sides, and put the feed at the two ends.
For moving the chickens: if you put something tasty in a bowl, and bring it to them each day, the chickens will usually be happy to follow that bowl. So you may be able to open the coop door, walk to the tractor with a bowl, put the bowl in, shoo in any stragglers, and close the tractor. Start with the tractor near the coop, and move it further away with time. The "something tasty" can be kitchen scraps, or it can be wet chicken food. I prefer wet chicken food, because they cannot pick up a bite and run off with it. This forces them to stay where the bowl is while they gobble the "treat." I don't know why they like it so much better wet, but they do, and that is convenient for me!
Alternate way to move the chickens: get a puppy play yard, or a dog kennel that comes apart into panels, or a roll of chicken wire and a few posts, and make a path from the coop to the tractor. Let the chickens go along that path, walk behind to shoo the stragglers in, and close the trailer.
Third option for moving the chickens: carry them one by one. Go into the coop and close the door, grab one.... If you do it every day, they should get used to it, and catching them won't be too hard. And it will give you lots of practice in catching & carrying chickens. For putting them home at the end of the day, I would go with some other method, rather than crawling around in the tractor to catch them.