The Chevy Chases Save the Date

So, now that we are approaching the 10-month mark, it's time that I finally make a decision on our STDs and get them in the mail. I've been looking online and messing around with ideas since February, but now I think I've designed one I really like. I was messing around in Illustrator one day trying to design a monogram, and I happened to glance up at the bulletin board behind my computer where I spotted this (personal photo):

Since we have decided to send STDs only to the out-of-town friends of me and Mr. CC, I thought a fare card might be a fun idea to incorporate DC. Here is what I came up with for the front:

We plan to order 4x6 postcards from overnightprints.com (I've heard great things about them, their prices are good, the samples they sent me were good, and they constantly have sales). I'm still tweaking it a little and have yet to design the back, but I plan to get them out later this month.  For the back, should I stick to the farecard theme and modify this (personal photo):

I'm not sure how I'd modify it exactly, but I'm sure I could come up with something ... or I could just have a standard postcard back, where I list the important info and our website list on the left and put the recipient's address on the right. Thoughts?