As for mirrors, there are extensions you can buy for very little that snap onto your existing ones.  I had a pair and they worked well. 

https://www.amazon.com/Fit-System-3891-Universal-Trailer/dp/B001AJH1HK/ref=sr_1_4?keywords=Extended+View+Tow+Mirror&qid=1553533659&s=gateway&sr=8-4

I went with the Swifthitch camera. It comes with a pretty nice stainless steel ball with adhesive to mount to the T@b. It works really well

I actually have found that 99.9% of drivers have been completely reasonable about our 'presence' on the highway. Polite & patient. 

It surprised me at first, I expected folks to be in a big hurry, and intolerant, but no!

I take the same attitude as @GatorEgg, and pay attention to what's ahead of me, letting the folks behind me do the same. I've got enough to worry about here up front!

I'll keep a close watch in the side mirrors for 'passers', but that's all I can really do, is be aware.

ChanW said:

I actually have found that 99.9% of drivers have been completely reasonable about our 'presence' on the highway. Polite & patient. 

It surprised me at first, I expected folks to be in a big hurry, and intolerant, but no!

I take the same attitude as @GatorEgg, and pay attention to what's ahead of me, letting the folks behind me do the same. I've got enough to worry about here up front!

I'll keep a close watch in the side mirrors for 'passers', but that's all I can really do, is be aware.

And truckers are pretty good at flashing their lights 9s you know you are good to change lanes.

Ok, so what is behind you is important.

emergency vehicules often comes from behind and all bit police cruiser have the acceleration to pass when ever they want.  Some roads are just way to dangerous to attemp passing w/o the vehicule in front slowing down or moving a side just a tad.  

But all this can not happen when you just look foward, thinking that what is behind you is none of your worries.

i am a Paramedic and a traveler.  In our neck of the wood, we only have one road and it is a two lane with only a couple passing area, many turns and many hills!  And that road is more than 400 miles long, no divided highway at all, no service road, hardly any dirt roads parrallel to this.  So sharing the road is very important.

so not taking care about what is behing you, when you are simply driving around, and site seing at the same time ( yep, the panorama is also very nice) creates a lot of frustration to the people following, and at one point, some will take a chance and double when it is not the right time.  So seeing what is behind you allows you to slow down a bit when a passing area is available, and or move a bit to the side and slowing down will let some drive by in a safe manner.

it will not prvent tailgaters, but it will rduce pressure from time t time.

the paramedic in me will thank you by hazzard blinking of some kind of signal light if I am in my personal vehicule.  

Well, I'm always a courteous driver, driving the speed limit in the right hand lane.  It is the speeding tailgaters who are making it unsafe.  What kind of person inches up to a foot behind your vehicle?  

I'll let you know.  I have one of these on order, but only because Costco has such a good return policy.  I am skeptical that the license plate light and the camera placement can coexist peacefully.  But I'll give it a try.

I see from the manufacturer's website that it released new firmware in November 2018.  I am hopeful that the bad reviews are because the prior firmware was buggy and the update corrected the connectivity issues.

No joy. The top of the frame where the camera is mounted sticks out too far to get it up and under the license plate light. Thus, there’s no way to install it using the existing license plate screw holes. There are two tabs included with the kit that I suppose you could use to lower the whole frame and license plate, but I think the camera would then block the light that illuminates the plate. You wouldn’t be legal to drive it at night.  Drag. Back it goes. 

I just purchased the Nucam wireless camera (thanks @falcon1970) for my 2020 T@B 320s Boondock Edge. Now I'm trying to figure out where to install it on the back of the camper using the magnet on the camera. I'm thinking about the area above the license plate (see attached photo). There is a screw there and I could get someone to install a metal plate for the camera's magnet to connect to. I'm wondering if the camera would be high enough to view vehicles behind the trailer? (about 3 1/2 feet from the screw to the ground) Or maybe I should try to install the camera higher on the bottom part of the Yakima basket? I will be using to camera for backing up purposes as well as seeing vehicles behind me on the highway. Thoughts?

@lisaco
Looks like a good plan. 42" should be high enough to see vehicles behind you and certainly enough for backing into a campsite.  If you mount it outside the trailer I would rig up some sort of safety cable as well.  That magnet on the camera is pretty powerful but vibration and potholes may slide it off the metal plate.
I mounted mine on a tripod sitting on the bed in my 400 and looking out the rear window.  That puts the camera at about 70" off the ground.  42" or 70", the view will be about the same if you have a semi right on your tail!

The orange bags are 5 lb sandbags from The Sandbag Store.  The idea is to keep the tripod and camera from bouncing around when I go over the whoop-de-do's on our Interstates.  If the tripod moves out of position the camera focuses on the window and not through the window.  Rather disconcerting until I realized what was happening.

I tried mirror extenders on my Tacoma for about a month, and I gave them to someone to drop off st Goodwill. 

Two nights in in a row, I almost T-boned a car in a roundabout because the mirrors hid the cars from my vision. Scared me!

If you use extended mirrors, be very careful of the big blind spot. 

I took Atlas’s advice and anytime I tow our 400 we leave the front and rear shades open to allow for a great visual opening through the trailer.  This allows me to see whomever is behind the trailer while traveling down the road.  If for whatever reason we leave a jacket or hoodie hanging on the hook at the front of the trailer we stop and remove it.  

I have several theories why people might tailgate.  I think that since the 400 has such a high profile, people get behind the trailer and stay up close in an effort to draft (if you will) and reduce the effects of wind drag on their vehicle on long stretches of interstate highway driving.   Others might be trying to see inside the trailer and determine the manufacturer.   The last time I was at the factory I picked up an extra nuCamp emblem, mounted it on the drivers side of the trailer and suggested to them they put an emblem on the drivers side too (as opposed to just the passenger side) so people can identify who built it.  

But I agree, it’s frustrating when people tailgate on interstate highways.  There have been times when this occurs on long stretches of interstate and if it irritates me I turn on my turn signal and will get over and ride in the passing lane if conditions permit.  This usually works as the tailgater normally moves on up the road and things return to normal.  When I see traffic ahead starting to slow down I also flip on my 4-way emergency flashers to alert drivers behind me that a problem is coming up and to eliminate someone rear-ending the trailer.  

Distracted drivers who text and drive are the biggest safety concern out there today (along with alcohol & drugs) and this is another reason you need to know who’s behind you.  I’ve seen it all and it’s a sad day when professional semi-truck drivers are texting, watching TV, etc. and not paying attention when hauling a 10K pound plus cargo laden rig down the highway and swaying from dude to side, going off the edge of the road, etc.  You know who the real professionals are by their attentive and courteous actions.