ffmpeg: using vidstab{detect,transform} on parts of a video
It is possible to use the select filter to select scenes for stabilisation and inclusion into the final result - see the example below. It seems that select is slow for skipping over unwanted material. This does not create any intermediate files except the *.trf file. In my example I am not using audio, which would have to be selected likewise. 

#! /bin/bash

f="20191128_215245A.mp4"
x="select='between(t,5,10)+between(t,15,20)',setpts=N/FRAME_RATE/TB"
s="vidstabdetect=stepsize=6:shakiness=6:accuracy=9:result=foo.trf"
y="vidstabtransform=input=foo.trf:zoom=1:maxangle=(1*PI/180):smoothing=30"
z="scale=1440:-2,unsharp=5:5:0.8:3:3:0.4"
a="-an -tune film -r 60 -crf 26 -vcodec libx264 -preset slow"

ffmpeg -y -i $f -vf "$x,$s" -f null -
ffmpeg -y -i $f -vf "$x,$y,$z" $a foo.mp4