Not possible you would get 75ms delay even if you could 

In order to get ‘stereo’ both Roams would have to ne on your WiFi. Bluetooth can only connect to one speaker, you need to the rely on WiFi to send the necessary signal to the second, by grouping them. You’ll still need to deal with the delay that ​@skullc speaks of, as the Sonos system is not designed for the usage you’re intending. It may not bother you, though. 

I think you may have misspoke a little bit here. Ideally, you want to have your Roams setup as stereo pair, connected to WiFi.  You would bluetooth connect to one of them, but since they are already a stereo pair, you’ll get stereo, left and right channels, over both speakers.   Grouping would apply if you didn’t set the 2 Roams as a stereo pair, and you would not get stereo in that case.

I’ve found that a bluetooth connection to TV audio is ok for casual TV watching.  If the TV is just on while you’re doing other things in the backyard. it will probably be fine.  If you’re trying to have a outdoor movie night, or ‘seriously’ watching a game, you might find it a little lacking.

 Hard to get beyond the egregious typos in my response.

Ah, yes, I see. Grouping wouldn’t apply unless they were two separate ’mono’ rooms. You’re absolutely correct, setting them up as a stereo pair would require WiFi, which is indeed what I meant to say. However, if you wanted them as two individual rooms, it would still suggest grouping (and WiFi) , since the vast majority of devices don’t have the ability to send two simultaneous Bluetooth streams. 

Ok thanks everyone.   I do have wifi back there and will only use for music (Spotify) and games.   I'll see how it goes with the delay but to be honest, as long as I’m not looking at announcers talking, I don’t think I’ll notice the delay.

Jeanne