Modem/Router placement

Does the laundry area have a shelf? If so, can you put the gateway outside the enclosure? 

Yes, but it is all full of stuff. I was looking for a plastic option

Get the model number off it and do an internet search for a plastic cover or put up another small shelf for the gateway.

Could remove the metal cover, leave it off or purchase thin plastic like sheet used in fluorescent light fixture, cut to size and drill some holes… but installing the equipment outside the enclosure on a wall mounted shelf is likely best and should provide better ventilation.

For many of the newer apartment complexes a communication enclosure is standard often placed in the main bedroom wall in closet, or hallway coat storage area but have seen some in laundry areas. 

Alternatively, if you had a personal WiFi system, never a bad idea with Att Internet, could the base unit be placed in a more optimal spot away from the interference?

There is probably inadequate ventilation in the enclosure to properly cool a device such as a BGW320 gateway, especially when it is providing Wi-Fi service.  So, disabling Wi-Fi and getting your own Wi-Fi Router/Access point that you locate external to the enclosure is an option that might help with both issues.  Moving the Gateway to the shelf would definitely help with the cooling and the Wi-Fi, though the humidity in a laundry room could be a concern.