I'm interested to see what you have planned for the tongue. As it is it gives me the heebbie-jeebbies, but I understand that it's a work in progress.
The point where the tongue meets that first cross tube is a hinge point that few seem to understand. Running a continuous tube past that point, and preferably as Bob suggested, under the rest of the frame is the much preferred tongue construction method. It is frequently not done on trailers of this size built by folks on these off road oriented forums and doesn't seem to be too much of an issue, but note that even the 1/4t M101's are built with the tongue under the frame so those Engineers felt it was worth something.