I did mention in a lost post here that some members would disagree with our assessment of John Twist. Some memebers have incdeed come to his defense, saying that all he wanted was some help to run the ranch. Although I am not sympathetic to John Twist, I tend to consider this a possibility.
IN any case, I think that in spite of John Twist, Ennis and Jack could have made things work. Ennis provided the necessary discretion whereas Jack provided the push to live a little. They complemented each other quite nicely, and I think they would have worked well together up in LF.
But it could haver been "relatively" safe, do you think? Perhaps it would have been worse had they lived by themselves in the midst of or near a disapproving/hostile town. As I mentioned, the Twsit ranch provided some cover, if they somehow managed to keep the elder Twist under control...
I think that you know my opinion about John Twist. And it is not based only on one thing - it is based on all the possible data we have about him in the SS and the movie. But even if we want to stick only to the movie, we have enough material to get the picture how awful the old man was to Jack. I dislike him for being so bad to Jack, never showing him a real love, but only discontent with him as a person. And when it comes to Jack, I am even more sensitive to this kind of treatment!

I am not sure if you think that Ennis&Jack could keep the nature of their relationship private, but IMO the old man already had a pretty good idea about that. When he spat in the cup with disgust ... I think that he was just expressing his attitude towards Ennis and his "friendship" with Jack.
IMO, the only way that John Twist would've accepted Ennis on the farm was if his own selfishness surpasses his disapproval of Jack and his relationship with Ennis. I think that their relationship would be very very complicated, with one little buffer zone - mrs Twist!
I am not sure how this would work
, but if it would - than I can accept that LF could've been a better "cover" for them than some unknown place.
OMG, if only they come to this choice - LF or elsewhere.... :\'(