In short my question is: Would you take your fiancee and move away from all your family and friends for at least a couple of years in order to rapidly accelerate FI and potentially provide significant career opportunities in the future?
yep! did it. I am from the Twin Cities and my boyfriend is from Pittsburgh (I know those probably sound like hokey midwestern small towns compared to NYC ;) but they really aren't). after I finished grad school in Pennsylvania, we moved to Tulsa. it has definitely had its ups and downs, but I'm glad we did it (it was for a great job opportunity for me, right out of school which can be a tricky time to find a job; he was unemployed for a few months but then found something which is working out pretty well) and we are definitely treating it as a short-term adventure, although we have been here for two years and don't have a specific deadline. it is REALLY nice having good incomes and a super-low COL.
it is a little hard being so far from our families, but I was already living far from mine for the 2 years of grad school (I'm actually a little closer now!) I just use a Delta Amex card for literally every purchase, and those miles help offset the travel costs. I read somewhere that doing something like this early in your life together can actually really help strengthen your bond, since you don't have a lot of interference from either family and you get to start your own traditions together. that sounds cheesier than I intended, but I do feel like being on SUCH a different adventure together (prior to the move my boyfriend had never been west of Indiana! and it was definitely a bit of culture shock for us) has been a good bonding experience :)
Also, would like to hear from those of you who live or have lived in the midwestern states with regards to what you enjoyed about them, and how did you deal with some of the perceived downsides such as tornados / isolation / ideological differences / racism (we're a mixed couple) etc.
tornados... I don't really worry about these that much (although my mom does :)) we do have a basement which is for some reason rare in this part of the country, so that's nice to have "just in case."
isolation/ideological differences haven't really been a problem. before we moved we were part of a running/drinking club with many global chapters, and it turns out Tulsa had a great one that was active and full of people in their 20s and 30s, so this is our main social group and tends to be generally pretty aligned with our own ideological views (with enough diversity to keep it interesting!) we are really never bored... the thing we miss most about Pennsylvania is definitely its superior options for hiking/camping/trail running, but we're surviving :)
racism... I actually do notice people occasionally saying shit that is kind of shocking to me (not out-and-out using racial slurs, but just things where I think to myself... wow... really?!), but it's always older people. not that that makes it okay, but at least the younger generations seem to have it figured out :) I'm white though, so there definitely might be more subtle stuff that I'm completely oblivious to that would be bothersome.
all that being said, Tulsa is pretty different from a town with a population of ~20k... I have never lived anywhere like that so I don't really have input on it! like others said, doing some research on job options for your fiancee seems crucial. I just wanted to weigh in on the idea of moving across the country short-term since it has worked out well for us!