A way to bind a layer's transformation property key to a layer marker.

You can use an expression to look at the time of two markers and then use a linear expression and a defined start and end point for the move. 

This expression will start any layer on the left side of the screen and move it on a straight line in X to the position where you want the layer to end up. 

sFix = ([100, 100] - scale) /100;
lyr = sourceRectAtTime();
w = lyr.width + lyr.left;
h = lyr.height;
t = time;
// find two markers and create a move
if (marker.numKeys == 2){
	st = marker.key(1).time;
	et = marker.key(2).time;
	sp = [- w, value[1]] + [w * sFix[0], 0];
	ep = value;
	ease(t, st, et, sp, ep);
	}
else{
	value
}

The expression compensates for scale, will work with text layers no matter the paragraph justification, and will work with any footage or solid layers if the anchor point is centered. If your shape layers have a stroke, you'll have to compensate for the stroke in the sp property.

I have many of these expressions saved as animation presets, but they are mostly based on the layer in and out points instead of markers. The expressions allow me to create slide shows and explainer graphics by choosing the move I want, setting layer in and out points, and positioning the layers where they need to rest. Here's one that I use a lot that will fly a layer in from the left side of the screen and bounce it to a stop. The timing is based on Sliders. The resting position depends on where the layer is before you apply the preset. 

https://www.dropbox.com/s/tewk9s88mpkmnou/flyInBounceDropOut.ffx?dl=0

Download the preset, position a layer where you want it to land, then use the Animation Menu to apply the preset. 

There is no direct way to link keyframes to markers. As a workaround, you could write some expressions, which time-remap the transform properties based on the marker position. That would mean the keyframes stay in place, but the expression, which acts on top of the keyframes would sample the property value from different time points if you move the marker.