Nah, she's getting out now. They can't possibly keep the series going without some new storyline - the "oh, is she going to escape?" has been milked now!
The house is very rural - I reckon they are within reach of the border.
I reckon the gunshots will have alerted some everyday country folk who are sympathetic. Hopefully, actually part of what was Mayday.
They'll take her and the baby in and sneak them over the border.
That means the Commander falls, letters are one thing, but, a Handmaid is another. He has to run. Serena either dobs him in, or gets in touch with that journalist and gets to Hawaii.
Nick's a goner. He's going on the wall, not sure why yet, but, he will, though June tries to save him.
In series 3 June and Serena work together to find the Commander and bring down Gilead.
And they all live happily ever after