I based this trailer on the Grumman 2 design by Andrew, which can be found in the Design Library under the Design Resources at the top of the screen. It is not an exact copy, but you should get the idea.
Hope you enjoy and learn a little along the way.
Here is a link to the video series playlist on YouTube
http://www.youtube.com/playlist?list=PLE232575796E3DB49
The videos below are on screencast, but they will only work when I have enough bandwidth available.
Creating the profile.
http://screencast.com/t/US9TpHae
Laying out the roof, door and floor in the profile.
http://screencast.com/t/BKkmbKDISwN
Laying out the bulkhead and shelving.
http://screencast.com/t/4bVWgSo3W3Om
Final laying out of the profile.
http://screencast.com/t/hhT6VOcPy
Creating out shell in 3D.
http://screencast.com/t/SjNOrhh3
Creating door and window in 3D.
http://screencast.com/t/77HwG0qdKo
Creating hatch in 3D.
http://screencast.com/t/Ntlrwbdx8DV
Creating the floor, bulkhead and shelving in 3D.
http://screencast.com/t/5gsfWNwWYifx
Creating sides in 3D.
http://screencast.com/t/ZIrxroThEn6
Adding doors to the sides and then putting various parts toghether.
http://screencast.com/t/AENRkc9NPH
Creating the frame in 3D.
http://screencast.com/t/7jA34DFzS
Adding an axle, wheels and coupler to frame using components from the 3D warehouse.
http://screencast.com/t/K5bCDxacL
Putting it all together, showing how to make colors transparent and a few other tips.
http://screencast.com/t/Wom8nvmVZkrc
Creating the fenders in 3D.
http://screencast.com/t/BL2F1au95
Positioning fender and copying using the array feature.
http://screencast.com/t/UZZcVd1rCj
Creating holes in the bulkhead for storage.
http://screencast.com/t/cBkvgaZAvA
Creating mattress and rotating open hatch and door.
http://screencast.com/t/WCU4Iv8bhlbk
Dan