The fitting on the TT is kind of "T" shaped (see attached pix).
So, the crank handle fitting is shaped accordingly.
If you have access to the tools, you could fabricate a fitting out of a deep socket wrench that is a slightly larger diameter than the rod. Take the socket, clamp it gently in a vice, then cut the slots into it using an angle grinder (while wearing safety goggles and hearing protection
). Then, use the socket with any handle (plus extensions if you have them), and you'll be good to go.
If you have this fitting, strange that you didn't get a crank handle. You could try contacting your dealer or Forest River...