如图,矩形\(ABCD\)的边\(AB=3cm\),\(AD=4cm\),点\(E\)从点\(A\)出发,沿射线\(AD\)移动,以\(CE\)为直径作圆\(O\),点\(F\)为圆\(O\)与射线\(BD\)的交点,连接\(EF\)、\(CF\),过点\(E\)作\(EG⊥EF\),\(EG\)与圆\(O\)相交于点\(G\),连接\(CG\).
\((1)\)试说明四边形\(EFCG\)是矩形;
\((2)\)当圆\(O\)与射线\(BD\)相切时,点\(E\)停止移动,在点\(E\)移动的过程中,
\(①\)设矩形\(EFCG\)的面积为\(S\),求\(S\)的取值范围;
\(②\)求点\(G\)移动路线的长.