Hi, I'm new here 
I'm in the market for a router to cover a 3000 sq ft, 2 floor house with thick concrete walls. I live in the US but the house is in a different continent, so can't try different ones, I'll be installing it next month.
They have 25/5mb fiber service, the gateway modem provided by the ISP (horrible wifi coverage) is located in one side of the first floor; can't move it.
I currently have a couple of DD-WRT routers in 2nd floor as wired AP's. But the ethernet cables (running outside the house) get damaged due to weather, cats in the house..etc
I can't / not allowed to run cable inside the mother in law's house :/
Max 15 devices connected (2.4 & 5Ghz), but mostly 4-5. No usb support, file transfers between devices capabilities; just a good wireless signal to connect to the internet throughout the house. No nearby wireless interference.
This leaves me with the option of a single device, I understand it's not the best option; but oh well.
I need it to be rock solid since I won't be there to troubleshoot..etc
Can I get away with T-Mobile TM-AC1900? Or ?
max $250 if must.
Thanks!

I'm in the market for a router to cover a 3000 sq ft, 2 floor house with thick concrete walls. I live in the US but the house is in a different continent, so can't try different ones, I'll be installing it next month.
They have 25/5mb fiber service, the gateway modem provided by the ISP (horrible wifi coverage) is located in one side of the first floor; can't move it.
I currently have a couple of DD-WRT routers in 2nd floor as wired AP's. But the ethernet cables (running outside the house) get damaged due to weather, cats in the house..etc
I can't / not allowed to run cable inside the mother in law's house :/
Max 15 devices connected (2.4 & 5Ghz), but mostly 4-5. No usb support, file transfers between devices capabilities; just a good wireless signal to connect to the internet throughout the house. No nearby wireless interference.
This leaves me with the option of a single device, I understand it's not the best option; but oh well.
I need it to be rock solid since I won't be there to troubleshoot..etc
Can I get away with T-Mobile TM-AC1900? Or ?
max $250 if must.
Thanks!