I assume you are mounting a TV around 23-25" in size. No need to ad any extra blocking to mount in the area Jayco suggests.
There's blocking behind the wall where it's marked. If using lag screws make sure you drill the right size pilot hole.
The LED TV's now are so light weight isn't a problem.
In my Jayco 23RLSW I was limited in width for the bedroom TV because of a door way on each side of the TV.
I had to limit it to a 19". Think it only weighs 5 lbs. Stays in place when traveling with no issues.
If you buy a articulating mount, make sure it locks in place for travel.
Here's a place to look.
https://www.monoprice.com/pages/tv_wall_mounts