Steve,
I'd be nervous as hell about sliding the machine down a ramp, unless you can hold it back with a small winch or something. If it gets going too fast, it could tip over when the leading edge hits the ground, even if it did not want to tip while on the ramp itself.
It is quite a simple matter to roll the machine around once it is on the ground. I have moved all kinds of heavy machinery with old 1" or 1.5" round bars laid beneath them. You just need to use pieces that are long enough for both sides of the base to roll on. Ideally, use 3 bars, so you can keep moving the back one to the front as you push it along. You can even lay the bars down at an angle to the current path to steer the machine in a different direction. You'll need a crowbar to lift it a little now and then to get the next roller to go underneath it
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)