GWOD

I listen to 3 of the GMRS channels, open, 600, 650, 675. these are our locals. I just activated the standard travel tone on 600. and we are thing of swapping location for 600 and 675, since as I recall, 675 is the standard for Emergency communications. either way 675 makes a lot of sense if you are just listening or are starting your own repeater in an un-serviced area. All though our new equipment is capable,  We do not plan to use Narrow since it is not required on part95.   

I don't use GMRS simplex very often, but if I remember correctly, the unofficial 'standard' is 141.3 CTCSS.  I am unaware of any unofficial DPL standard being used simplex nationwide for travelers or emergency comm at this time, but others here may have more up to date info than I have.

Not at this time - GMRS is a Part 95 radio service.  The narrowband requirement was applied ONLY to SOME Part 90 radio service frequencies above 54 mhz.  - however, every commission administration change brings 'new' ideas to bear, so anything is possible in the future.