Hi Jeff,
I think it might be unrealistic to aim for a K-1 visa process to complete in less than 4 months.
My fiancee (Aussie) and I (USC from San Franciso) hav been fortunate that every step of the process has been much faster than we anticipated. But it still took time. I had a spreadsheet which tracked everything. We did EVERYTHING by the book, which required hours of reading the USCIS websites, visajourney.com instructions, forum posts, and advice, check and double-checking everything. It was fun that she and I could be together through the initial part of the visa petition process. You can follow our timeline below.
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19Jan2010 My fiancee came to San Francisco. She and I have been traveling back and forth many times. Since we didn't know how long the K-1 Visa process will take, we figured this will be her last visit before she can come back on an approved K-1 visa. She stayed to 16Apr2010 (almost the full 3 months allowed by the tourist visa)
23Jan2010 Mailed I-129F (return recp't & certified mail)
25Jan2010 NOA1 (website), noticed via snail mail 01Feb2010
26Jan2010 USPO return receipt arrived
27Jan2010 Check cashed
26Feb2010 NOA2 (website), noticed via snail mail 04Mar2010
06Mar2010 Petition received at NVC (website), noticed via snail mail 10Mar2010
17Mar2010 Packet 3 received (via email)
24Mar2010 mailed DS-230 to Sydney
18Apr2010 Fiancee returned to Australia (we didn't realize the paperwork will flow so smoothly and quickly.
19Apr2010 Fiancee requested for police certificate (in Melbourne)
21Apr2010 Fiancee medical exam
23Apr2010 police certificate received
_________ Medical results
_________ Send "ready for interview" to Sydney Embassy
_________ Interview appointment
_________ Visa Approval
_________ PoE