I think you're right on the money when you point out how unrealistic it would truly be for us to see Beth again. That's not to say that it's impossible, though, and the storyline potential for where to go with her now is intriguing, so I'm perfectly fine with seeing her again.
The only people who would be looking for her would be Maggie and Daryl, so I really can't see the whole group trying to find her after they escape from Terminus. It would have to be another miraculous reunion if they wanted Beth to reunite with the group.