Weird, I had written out a pile of stuff,but it did not show!
Check out visajourney.com, LOTS of info on RELATIONSHIP style visas. Checkout the K1, K3 and CR-1 forums. At the very top of those forums are stickies/guides on how to apply for each
http://www.visajourney.com/forums/index ... ge=compare this compares the 3 different visas, gives you the + and - of each visa
As well check out the new WIKI feature, as well the the Canada WIKI site,lots of info
http://www.visajourney.com/wiki/index.php/CanadaK1 (finace visa, not married yet) is probbaly the fastest, but check out the +and - of it above.
K3 is becoming less desirable, as it takes about the same time as a CR-1 visa. Cr-1 is probably the "best" visa as it costs less in the long run, can work right away, no travel restrictions, BUT it does take close to a year to obtain. Check out the + and - link above. Keep in mind you CAN travel/visit the USA while the visa process is ongoing, BUT it is up to the Port of entry (POE) officer, so do bring ties to Canada IE apartment lease, letter from employer, etc etc. And yes some do get denied entry! I traveled monthly to DC from Halifax,never had a problem.
Best of luck