It's a shame you've left it to last year of your 10 year green card validity to consider applying for citizenship. I'm guessing you'll have to scramble to get your citizenship process complete before your greencard expires. You'll also have to complete that before you move to the UK.
We went through the US to UK spousal visa process for my wife two years ago. Main obstacle you'll have is to show you have sufficient income and housing to accommodate your wife. Aside from that I would highly recommend getting a solicitor to help you with the process, the firm we used were amazing (Reiss Edwards, London), you can find my review of them on Google. The process is arduous but way faster, we got a response and my wife was in UK in 4 months of applying. Path to permanent residency is harder for immigrants to the UK, it's spousal visa for 2.5 years then extend for further 2.5 years, then apply for indefinite leave to remain (permanent residence) and then immediately for naturalization and citizenship (if you choose to do so).