Yeaaa...

Use all joint's and you will be able to run in 10.000 distance
I've tried running in 10.000 distance...unfortunately i delete the replay. ;-;
Glute, lumbar, and pecs are important to keep your balance.
The point is...balance.
Also,
try to not use Chest while free running.

chest is a bad option
dont use chest too often unless ur falling a side
thats when u can use the chest.

Ok I am pretty experienced in this field, and i can say there is no easy way to learn how to run or parkour or trick. Its practice. Now what i can help with is learning to balance your tori to continue a run or gain momentum. What i think of my arms of, are as weights used to counter offset balancing.

Now what i usually dont do is ever touch my chest unless im relaxing it to start a jump. You want to work with your lumbar and pecs. Never contract the pec of the current stepping leg. That is a sure fire way to fuck up your balance and flow and continue to not learn properly.

Now remember this is no easy way to learn to freerun, but you can make it easier by ditching the youtube run and trying to learn a custom run. You can use the youtube run format but change up certain things. The youtube run doesnt work forever. I have learned 3 custom runs i have made up myself that i am willing to share with anyone interested in them.

Now all in all i can say that to learn free running, focus on learning how to balance your tori, then try to string in a running motion. Then from that add in turns and such.

Hope i helped someone <3

I can't seem to land the first step of the youtube run
It keeps overshooting the ground then eventually i fall over.
I followed all the joints correctly, and the game settings, i just don't know what i've been doing wrong

The game settings could be wrong, try setting it to the spar mod <3

How do you return to a run when you have jumped

This all comes with practice. I always wondered the same myself.
What will help the most is experimenting on ways you can jump and experimenting on things you can relax, contract, and hold to make a realistic jump and landing. Just keep at it you will get better in time.

after a jump relax into the fall so it could look as smooth as possible, afterwards, land in a way to support a running stance.

I cant find any maps big enough...

There is a huge collection of mods with some enormous parkour mods :

http://forum.toribash.com/forumdisplay.php?f=18