Reference Image (dont consider the purple line): 
I bought a TL-WR940N to use as "Router 2" (R2), setted its internal LAN range to 192.168.13.x while the "super" network "Router 1" (R1) the range is 192.168.15.x. R2 have its WAN port connected to R1's Ethernet port, so its a LAN-WAN configuration.
I wonder if is possible to computers connected to R1 access the devices connected to R2 without needing to use another NIC, in this question (marked as similar before my edits) there's this interesting excerpt:
However, computers that are connected to the main router will not be able to communicate with the secondary router without additional configuration, and vice versa since there are two different networks.
I think i have access to some routing configuration on R2 (again, a TP-Link's TL-WR940N), and my question is if is really possible to make connections across those two networks, if yes what i need to config on both routers.
Thanks in advance for any helps!
