Comment 44 for bug 775117

lvscar came across the same solution I just found in the Arch forums:

Solving problem with slow cold start:
Some people still have problems with Thunar taking a long time to start for the first time. This is due to gvfs checking the network and Thunar won't show up before gvfs finishes. To change this behaviour, edit /usr/share/gvfs/mounts/network.mount and change AutoMount=true to AutoMount=false.

Nice to solve this, it was irritating!