you can take KMB bus No.N30
Here is the information:
Get On Point:紅橋,新墟街市 or 屯門市中心
Get Off Point:青馬收費廣場,東涌纜車站 or 東涌鐵路站巴士總站
Fee:$27.1
Times:90 mins(not included the walking times and waiting times)
But reminder you that the first bus leave from Yuen Long (East) Bus Terminus is 03:20a.m so that this bus will be arrived Tuen Mun at around 04:00a.m
KMB bus No.N30 Information:http://www.kmb.hk/chinese.php?page=search&prog=route_no.php&route_no=n30
Hope above information can help you!