CEN60 seems to be implying that even a Hawick extension is not going to happen.
If the Hawick line went through Melrose Rugby Club, it would also go through many houses on either side so, that can't (shouldn't) be a serious idea. The new bits of A6091 and A68 mostly don't use the trackbed, as Satellite will show. Only a short stretch just east of Melrose station is taken, plus 5 places where the roads cross the trackbed from Tweedbank to St Boswells.
The sat imagery of Galashiels is well out of date, as the line isn't even under construction! This is good as it shows what can and was done to fit the railway in. A track and platform was somehow squeezed in next to the A7. Beyond there, a long building was demolished, the line squeezed around the back of Asda and then straight through some sheds used by businesses. Amusingly, the map version shows the buildings, and the railway going through them. I don't recall going through any sheds on the train in 2017!
Anyway, looking at Galashiels illustrates that if the commitment is there, great things can be done. There is nothing physically from Tweedbank to Hawick that is any more daunting than on the 35 miles from Edinburgh.