Wow, that is one scary thought. That's a lot of trailer to have no brakes, especially in that terrain. You are very fortunate that you didn't find out the hard way that you had no trailer brakes.
Now that you have a little more experience under your belt, always check your trailer brakes as you pull out from home, out from a CG, or wherever. And it never hurts to periodically do this throughout a day of travel. I've done this gently at 60 or 65 mph...gently. I just want to feel a little tug to know that the brakes are getting the juice.
Just reach down while going slow (your driveway, or the CG drive) and slide your manual brake slider over some. You will feel the trailer tug on your TV substantially. If you don't, stay off the road until you figure out why.
Happy trails!