How do I keep changes in Edit mode when using Keyframes?

I want make an animation (in this case it's a door opening), play the timeline and then continue in Edit mode from the position that things are in when the timeline finishes. I've tried "Keep Changes" on the Keyframe and while that makes it LOOK like things are in the same place, as soon as you press play or go into Play mode, you find that everything is back where it was originally.

I'm finding it difficult to complete certain animations because of this. In this instance I'm animating the landing gear extending and retracting on a helicopter. So I made a little sliding door under the chassis using the Cutout tool. Once I've done that, the door is in the perfect 'closed' position. So next I create a little 'door opening' animation where the door comes down an inch, then slides back to reveal the cutout space. With me so far? Ok. Because this is where it gets annoying. I now need to place the landing gear in the space. But I can't because i seem to be caught in a catch 22 that I can't figure out.

You see the landing gear has it's own little unfolding animation ready for when it is deployed, and it has the reverse animation for when it's retracted. The problem is that I obviously can't place the landing gear when the door is closed because I won't be able to see when the hell I'm doing. Therefore I need to place it when the door is open. So the problem is that although I've done the animation for the door opening, that's just a keyframe recording that is not 'real' if you see what I mean. The final position recorded for the door is not where the door really is in Edit mode. It's still closed. So in order to achieve what I want, I have to move the door to the EXACT spot that I moved it to when I recorded the keyframe animation of the door opening.

I hope that made sense to someone. I feel like I'm missing something and there must be an easier way.