とりあえずこんな感じです。

//****************************************************************************
// Script for Tweener _bezier Option
// author nutsu
// version 0.2
//
// sample output : { x:460, y:100, _bezier:[{x:250, y:200},{x:355, y:150}] }
//****************************************************************************

var edgeArray = fl.getDocumentDOM().selection[0].edges;

var tmp  = [];
var tmp2 = [];
var turn = [];
for ( i=0; i<edgeArray.length; i++ )
	tmp.push( edgeArray[i] );

var e0 = tmp.shift();
tmp2.push( e0 );
turn.push( false );
joinX0 = e0.getControl(0).x;
joinY0 = e0.getControl(0).y;
joinX2 = e0.getControl(2).x;
joinY2 = e0.getControl(2).y;

while( tmp2.length<edgeArray.length )
{
	flg_join = false;
	var min_value = -1;
	var min_pos   = -1;
	var min_index = -1;
	for( i=0; i<tmp.length; i++ )
	{
		var ed = tmp[i];
		var p0 = ed.getControl(0);
		var p2 = ed.getControl(2);
		if( p0.x==joinX2 && p0.y==joinY2 )
		{
			flg_join = true;
			tmp2.push( ed );
			turn.push( false );
			joinX2 = p2.x;
			joinY2 = p2.y;
			tmp.splice( i, 1 );
			i = 0;
		}
		else if( p2.x==joinX0 && p2.y==joinY0 )
		{
			flg_join = true;
			tmp2.unshift( ed );
			turn.push( false );
			joinX0 = p0.x;
			joinY0 = p0.y;
			tmp.splice( i, 1 );
			i = 0;
		}
		else if( p2.x==joinX2 && p2.y==joinY2 )
		{
			flg_join = true;
			tmp2.push( ed );
			turn.push( true );
			joinX2 = p0.x;
			joinY2 = p0.y;
			tmp.splice( i, 1 );
			i = 0;
		}
		else if( p0.x==joinX0 && p0.y==joinY0 )
		{
			flg_join = true;
			tmp2.unshift( ed );
			turn.push( true );
			joinX0 = p2.x;
			joinY0 = p2.y;
			tmp.splice( i, 1 );
			i = 0;
		}
		else
		{
			var min1 = (p0.x-joinX2)*(p0.x-joinX2) + (p0.y-joinY2)*(p0.y-joinY2);
			var min2 = (p2.x-joinX0)*(p2.x-joinX0) + (p2.y-joinY0)*(p2.y-joinY0);
			var min3 = (p2.x-joinX2)*(p2.x-joinX2) + (p2.y-joinY2)*(p2.y-joinY2);
			var min4 = (p0.x-joinX0)*(p0.x-joinX0) + (p0.y-joinY0)*(p0.y-joinY0);
			if( min1<min_value || min_value<0 )
			{
				min_value = min1;
				min_pos   = 1;
				min_index = i;
			}
			if( min2<min_value )
			{
				min_value = min2;
				min_pos   = 2;
				min_index = i;
			}
			if( min3<min_value )
			{
				min_value = min3;
				min_pos   = 3;
				min_index = i;
			}
			if( min4<min_value )
			{
				min_value = min4;
				min_pos   = 4;
				min_index = i;
			}
		}
	}
	//最近傍に連結
	if( flg_join==false )
	{
		fl.trace("debug>>" + "join nearest point." );
		var ed = tmp[min_index];
		var p0 = ed.getControl(0);
		var p2 = ed.getControl(2);
		if( min_pos==1 )
		{
			tmp2.push( ed );
			turn.push( false );
			joinX2 = p2.x;
			joinY2 = p2.y;
		}
		else if( min_pos==2 )
		{
			tmp2.unshift( ed );
			turn.push( false );
			joinX0 = p0.x;
			joinY0 = p0.y;
		}
		else if( min_pos==3 )
		{
			tmp2.push( ed );
			turn.push( true );
			joinX2 = p0.x;
			joinY2 = p0.y;
		}
		else
		{
			tmp2.unshift( ed );
			turn.push( true );
			joinX0 = p2.x;
			joinY0 = p2.y;
		}
		tmp.splice( min_index, 1 );
	}
}


var lastpos = "";
var option = "_bezier:[";
if( confirm("Reverse the curve?")==false )
{
	for( i=0; i<tmp2.length; i++ )
	{
		var ed = tmp2[i];
		var p0 = ed.getControl(0);
		var p1 = ed.getControl(1);
		var p2 = ed.getControl(2);
		option += "{x:" + p1.x + ",y:" + p1.y + "}";
	    if( i==tmp2.length-1 )
			lastpos = (turn[i]) ? "x:" + p0.x + ", y:" + p0.y : "x:" + p2.x + ", y:" + p2.y;
		else
			option += ",";
	}
}
else
{
	for( i=(tmp2.length-1); i>-1; i-- )
	{
		var ed = tmp2[i];
		var p0 = ed.getControl(2);
		var p1 = ed.getControl(1);
		var p2 = ed.getControl(0);
		option += "{x:" + p1.x + ",y:" + p1.y + "}";
	    if( i==0 )
			lastpos = (turn[i]) ? "x:" + p0.x + ", y:" + p0.y : "x:" + p2.x + ", y:" + p2.y;
		else
			option += ",";
	}
}
option += "]";
fl.trace( "{" + lastpos + ", " + option + "}" );

あんまりテストしてないのでまだまだバグるかもですが。