Wow, its been a long time since I posted the original of this thread, guess I owe an update and product review, huh?
I love my DEZL. When towing I keep it in truck mode all the time. I put in the height and length of my set up and it keeps me on the roads that it knows can handle me. I do watch for low hanging things like trees and power lines which are impossible to predict. It also keeps me off routes that require sharp turns I cannot make.
My only issue with it was when I first got it. In order to get it out of demo mode I had to take it for a drive, only a couple hundred feet, but I didn't see anything that said to do that in the destructions. Once out of demo mode, everything works as advertised.
Basically, I'm very pleased with my Garmin and it comes with lifetime maps and traffic if you get the LMT model.
Thanks Brian.
I have been wrestling with the GPS decision.
I have CoPilot on my iPhone and am used to it. It has bugs but we get by. I use RV mode with a height of 13' which is working OK so far with the same application of common sense that you use.
I also have OilTrax Canada on my iPhone and I need it for work. Its a Garmin emulation that is very flaky, but if I kick it a few times it gets me where I need to be.

I am seriously considering a DEZL 560 which will run OilTrax in native mode, but I will likely have to pay for OilTrax for a second time (another two hundred bucks) to get it on the Garmin.
Or I can buy a series 3 iPad, buy the $150 high-definition truck upgrade to CoPilot and go on from there. The iPad will also run OilTrax in its flaky emulated mode without spending any more money. And then I have an iPad that I can do all kinds of silly things with moving forward.
I lean towards the iPad and CoPilot, but decisions, decisions. I am reluctant to spend the cash on both, but if consider 'belt and suspenders', bearing in mind I need OilTrax for work and they won't pay for it directly, that may be the smarter decision.
Geo