A standard Explorer Box is based on a 4’x6’ trailer frame. When building one to the plans, the axle is located 27” from the rear of the trailer. This provides a balance between good tongue weight and having space for a side compartment. Depending on how you build your Explorer Box, other axle locations work, although they may require some adjustments. Most flat bed utility trailers can be adapted to work as a starting point for an Explorer Box.

Bolt Together Frame Kit
For many home-builders, a bolt together frame kit is a cost effective starting point for building a Tent Topped Camping Trailer. They are available in a 4’x8’ model from many sources. Harbor Freight is probably the most well known supplier of them. In the Pacific Northwest I prefer the Fred Meyer or Bi-Mart versions because of their straight tongue design. Some may choose to use the extra length for an extended front deck or a location for a set of bike racks. Here is a customer write up about converting one to be a 4’x6’.
Welded Frames
Fully welded frames are another option. These are a good choice if you plan on doing off-pavement towing or want more flexibility than a bolt-together frame kit can provide. For information on the ones we offer visit Welded Frames page.
You Weld Frames
If you are an experienced welder, you can build your own frame. Synthesis Engineering Services has some good detailed plans available for a 4x6 frame. Their plans come with illustrated instructions, detailed drawings, material and components list, and lots of options. For additional information and to purchase, visit Synthesis Engineering Services Trailer Plans.