Will using a second wireless router as a wireless AP LAN-LAN cause a bottleneck at the LAN port, since my router is capable of wireless transfer speeds of up to 300 Mbps and my LAN port is only 100 Mpbs? I do a lot of file transfers between devices on my network that are only reached by my second AP. Would it be better to create a separate network and have it wired LAN-WAN or keep my current setup of LAN-LAN? I have four devices that connect to the AP, and about 15 devices that connect to the primary router. I am not concerned about the devices connected to the first router communicating with devices connected to the second router.
You cannot, ever, reach 300 Mbit/s net speed on 11n WiFi. It’s usually about half of it—150 Mbit/s.
Of course, this is still more than 100 Mbit/s. So yes, any WiFi-LAN transfer will be limited to 100 Mbit/s. WiFi-WiFi transfers are not subject to this limitation.
I don’t quite get the next part. You better draw some graphs showing what you mean. ;) Of course, you cannot work around the WiFi router’s limitations. To get full 11n speed, you’d need a Gigabit-speed wired network.