Hey,
I know this is late but I'm from the UK too and am doing the whole conversion process in North Carolina. I don't know if your fiancee is still going to do the pre-reg year in England or not (I'm personally glad I did because I learned pretty much ALL my clinical knowledge in that year, and I can still be a pharmacist if I ever move back without re-taking the final exam), but if she isn't I'm not sure how that'll work since I had to provide proof that I was a registered pharmacist in another country before being approved to take the FPGEE.
Be aware that the FPGEE is only offered twice a year. I got my green card (also married an American!) in July and felt that I wouldn't be ready to take the FPGEE in September so ended up having to wait until April. I studied the whole APhA FPGEE study guide and only one question on the whole exam was from that book...everything else was just my memory from England I guess. But thankfully I passed. It then took a good 5 months until I got my certificate (in the mean time I took the TOEFL), so be prepared for the wait. I didn't look for an internship until I got my certificate. I really wanted a hospital pharmacy internship but I assumed it was as competitive as it was in England so I went for retail. I sent out my CV, called places, went there in person, and all the pharmacists at the stores wanted the help, but the upper management said they either didn't take foreign graduates or didn't want to spend the time verifying I was legitimately an intern. As a last resort I was offering unpaid but even then no-one took me up on the offer. I decided to just give hospital a try and said I was looking for an unpaid internship and all 3 hospitals called me back inviting me for interview, and all ended up offering me a paid position. It was great! I finished my hours in October, just took the Naplex and passed, and am going to take the MPJE NC in a week or so.
Let me know if you have any questions, I would have found it so useful to know someone who already did it recently.