I've with JB - You should save the money and get an ER-4. The processor is the same.
POE can be done in the switches, so no need for that in the router.
The ER-4 is nearly half the ER-6.
I already ordered the pieces. Thanks for your input though. I needed a router with 4 ports for my 4 rooms plus the incoming port. I plan to use and learn everything about it.
So each room will be its own network?
Each room will have an 8-port switch because everyone has a lot of devices.
And since those switches will be going to a unique port on your router, they'll each be unique subnets (networks).
It's a good idea to have small switches in each room but normally you would do it like this:
If you wanted to have different networks inside the infrastructure, you'd use VLANs.
If you wanted to use PoE devices like security cameras, IP phones etc, you'd do PoE on the access switches.
If you'd want high performance the core switch would have 10 gigabit ports.
APs could also be connected in different places, for instance on the access switches.