L-1A - going to a POE in advance to get it?

Hey everybody! Have been devouring the handy info in all the various threads on this site - immensely useful. I was wondering if anyone had recent, specific information about doing the L-1A request at any POE vs. mailing in the application to be approved.

I am a Canadian citizen that's been working (from Toronto) for a U.S. company headquartered in California for 2 years now. They would like to promote me to a new functional management position working from HQ in California beginning in mid-August. They have an immigration lawyer working on the application for L-1A and supporting documentation for me. I have no assets in Canada but my lease (rent) is up on August 1 and I will be taking a scouting trip to California before then to find temporary lodging for the first few months.

My question is: can I go to any POE, say, drive to any of the bridges in Buffalo or even on my initial trip to California for scouting, and submit my L-1A application (and then come back to Toronto and wrap things up with my move)? Or do I have to do it only when I intend to continue on to my final destination? The immigration lawyer has recommended to purchase flight insurance on my one way ticket to the U.S. in the event that my L-1A application is declined. I have never made such a big move so I am a bit stressed out about literally packing up and then crossing my fingers for the border interrogation!

You can get the L1a in advance.

Wonderful. Does anyone have any experience doing this and can recount their story? Since Buffalo is under two hours' drive from where I live I am tempted to drive down there as soon as I have the paperwork in my hands.