And they are light! (The RC airplanes......)
Welcome Mercury. Just got our brand new 4100 King a few weeks ago and we'll be taking it on a 3000 mile shakedown cruise in March. It's been sitting in the driveway getting decorated. So far we LOVE it. We're not new to this program, had a Keystone Cougar 29BHS before, so we're easing in with relatively little problems. I've found a few very minor things we need to modify for our needs, but overall the trailer is really well done.
One word of caution, if you plan on hauling a heavy load in the garage, you will need to watch the options you add to yours. 18,000 pounds comes really quickly so if you want to stay within the legal limitations you will have to plan carefully.
And, as someone above said, make sure you have enough tow vehicle for the job. Legalities aside, it's just a so much more pleasant experience if you have the right tools for the job.