Is it possible to have the transaction log file write to a disk on a remote machine?
It is supported to have database files on network share, but Its inviting a disaster as any network blip might corrupt your database.


  Microsoft recommends that you store database files either on Local Disk or on Storage Area Networks (SANs).


You have to tune your data warehouse loading process. There are many parameters that can be tuned to have minimally logged operations and fast loading of data in sql server. e.g.


Trace Flag 610 - controls minimally logged inserts into indexed tables. 
I have listed few items in this answer.


Also, if you want to be proactive, then create an alert for Transaction log full, so you get notified when the log is about to get filled up.

Read up on :


The Data Loading Performance Guide
Load 1TB in less than 1 hour