I have done up to TS on the JBoots Heritage quest, and have just slacked at bringing an escaper along for TS and further.
Antonica is fairly easy, just one big loop. It CAN be done with propperly timed sprints, decent food for regen, light overall weight and knowing the shortest ways to the landmarks.
One good tip on Antonica, don't be afraid to take falling damage if it will save you time.
Commonlands was easier than Antonica was. Again, familiarize yourself with the landscape and find the fastest route to each landmark. A way to shave a few seconds off of your time would be to figure out how close you have to be to get the name of the area to appear for you. Cut as far away from that as you can while still getting the update and heading in the direction of your next destination.
I.e. If point B is West of point A, and you are approaching point A from the South, cut to the SW of point A so you can immediately head to point B. If you know point C is North of point B and you are coming from the East, then try to get a diagnal line to the NW so you skim the NE corner of point B. Then go due North for point C.
Hope that wasn't confusing, if it was just reread it a few times and maybe even draw out a diagram, you'll see what I mean.