While both rides are present, park them side by side and make measurements, so you know how much of the Dakota you want to keep and use. Its lots easier to determine where you want to cut something when you can look at them both.

Look at things like level points (with measurements off the ground in several places along both frames)with the rides parked at the same location in the garage or on the driveway. Determine fixed points on both frames that will be at least 12" away from the cut zone, so you will have reference points when its in pieces. Heights, widths, lengths, cross measurements, height off the ground, at several locations, at a given point on your garage is real useful when you need the new frame to be straight and flat. Write this stuff down, and take and draw pictures, its amazing how fast the memory fades over a couple months time. If you think maybe it might be something of value, make the measurement and write it down, its better to have useless info then to be missing something you wish you would have done.

Time spent looking at stuff side by side could be a life saver later. At least that's been my experience. Gene