Yes not much room! I kept truck for about 5 months than traded it on a 2026 Tundra. Now I'm stuck with custom seat covers front and back and a tool box for the bed. Plus floor matts.
I suppose it all depends on your requirements. I had two double cabs, a '15 and a '23. My kids were older by then. So special seats weren't needed. Everyone fit fine. I added a 12v port to the rear console for phone/game charging. All were happy. Also had a couple of buddies back there from time to time. They had no complaints. Are there dimensional differences with the 4th gen compared to previous gens?
I have a 2026 Pro and had a 2024 TRD OR, I wish Toyota made the Iso seats an option. I could fit in the rear seats (5'7'' 190lbs) in the regular tacoma but not behind the Iso seats
Go borrow a 90s Ranger extended cab from someone. Throw the kids in the back of it and go for a nice long drive. Bet you'll never hear a word about room in the back again.
My back seats are just for carrying groceries and other stuff, rarely people. Behind the driver seat no one would fit since I drive with the seat fully back. If I need to take passengers I take my SUV.
I recently sat in the back of an SR5 for 4 hours. My problem was the seat back angle not the leg room. It's certainly not roomy, but I never felt cramped. For reference, I'm 5'10, and the driver was about the same. The driver's son (about 5'5) complained there was no leg room and got the passenger seat.
I had one grandson ride for 8 hrs in the back seat. He had to sit sideways with his feet up. About 6'. Said he wouldn't do it again! Plus, he had to ride back the same way!