Providence, RI? Can I stop in & say Hi sometime? I'm off I-495 in MA, not far away.
All I know about the interstate numbering system is ones ending in odd numbers run nominally north and south and even ones run east and west. Also many state highways can have several names if they connect to other highways that then share a segment. Classic case the Golden Gate bridge is both correctly named highway 101 and highway 1.
The 3-digit Interstates are "loop" and "branch" routes that encircle big cities (like I-465 around Indianapolis), or bypass them to interconnect inter-city freeways (like the x80 series in the SF Bay Area).The numbers are formed by prefixing a digit to the number of the main Interstate route they connect to.
I'm not sure it makes economic sense to buy kits like the RBBB these days, unless you have special needs, as the integrated devices are now in the same range.Lets see, the Sparkfun Pro Mini (328p based) is $10 (currently out of stock, but presumably they will restock shortly). There are a lot of clones of the Pro Mini running around, depending on how you feel about using a cloned product.Pololu just announced a $13 32U4 based microprocessor, A-Star: http://www.pololu.com/product/3101Adafruit recently mentioned that they will be coming out with a Pro Trinket, that I think they said would be 328p based.The Digispark Pro is currently in kickstarter, and when it hits retail, it will be in that range.