Is this a good plan?

[HRutila]

That's a good question. Had I heard the request, I would have put your request on your strip and passed it along to the next controller, although in the case of last night, I was the "next controller," as I was working clearance delivery through tower."

A potential pitfall is that mentioning the SFRA may not result in the controller instinctually knowing that you needed a southwest departure. If you're really clear about it at the clearance delivery level -- "VFR southwest-bound to join the SFRA a X,500" -- that will help alleviate any confusion about where you're going.