You sound exactly like me when I was about to graduate. I also knew I wanted to be a CRNA, and I also wanted to have an adventure. I was fortunate enough that both worked out for me... Here's what happened in my experience...
My first job out of school was at Mayo Clinic. Not on an ICU, but I had formed a very good relationship with my manager, and I can say with relative assurance that I would have been able to transfer to an ICU within a year. I loved my job and was treated extremely well there.
But, like you, I wanted to get out of the Midwest where I grew up and see something different. Like you, I felt like there's only so much time where I wouldn't be tied down to one place, so I chose to take a job after about 6 months in a mixed ICU in the Northwest. This job was very, very different from the job I had at Mayo. Understaffed constantly, a very detached administration from the clinical realm, pay was not great, benefits sucked, mandatory overtime was initiated due to the level of understaffing, the list goes on. BUT, I got such important life experience out west. Would I do it again? In a heartbeat.
I gained a level of independence, confidence, maturity, and self-sufficience that I feel is now benefiting me as I'm going through CRNA school in an area that I never visited other than for my interview, where I know no one and nothing. I do feel that if I had stayed at Mayo, I may have gotten into CRNA school just as quickly, but the life experiences I got from moving out of my comfort zone are priceless. Not to mention, living in the west was absolutely amazing. I plan on setting roots out west as soon as I'm out of school.
As far as what you should do, in my opinion, it's up to what's most important to you. Hopkins will give you great experience for CRNA school, look great on applications, and you'll see patients you probably would never see elsewhere. If getting into CRNA school as quickly as possible is what you're interested in, it might be the best bet to stay put. It can be hard to get into an ICU as someone new to an organization (as a new graduate especially), and from my experience in my ICU, the hospitals that are taking new grads by the dozen into their ICUs may have some issues (not saying that all of them do).
But if your priority is going out west, then do it. If you have good recommendations from your MICU job and decent grades, you'd probably have a good chance in getting into an ICU. As long as you get good ICU experience and get good letters of rec from your peers, it shouldn't be a problem being admitted to CRNA school. Just remember, like nursing, CRNAs are needed everywhere, so even if you put off moving west until after CRNA school, it's not like you could never do it.
As far as whether or not you need MICU vs SICU, I'm not entirely sure how those are viewed on applications. I can say that in my class of 30, just about everyone has CVICU or trauma ICU experience. An ICU is an ICU in my opinion, and as long as you're getting sick, vented patients on drips, CRRT, etc. then I think it should prepare you well. You could always transfer.
Sorry for the novel
Good luck with everything. Tough decision.