It depends on the life you want.
I think that flight does NOT have the reputation it did years ago. Used to be best of the best - and in some markets, it does take only the best. But more often, it is all about "boots in the suit". Sorry. It disappointed me too!
I want to be very clear on this point - a bad day flying is so much worse than the worst day anywhere else. Patients die and, to some degree, we expect it. But, coming from the confines of the hospital - you gotta get your head around the fact that YOU CAN DIE or COWORKER(S) CAN DIE. Please don't believe that certain airframes, gadgets and other options make you superior to any other service or will keep you safe - by a 90%+ margin, the biggest factor in safety is good decision making as most crashes are a result of pilot error or MORE ACCURATELY failure of "flight crew" decision-making. However, making a good decision (aviation or clinical) in the flight realm is rarely black or white - it seems safety decisions would be, but based on crash details over the past decade, it would appear that even "good, experienced, flight crews" make many decisions in that lethal shade of gray. So, while aviation will be new and shiny - never forget that you have a voice and folks a LOT smarter and more experienced than me (or you, for that matter) have "gone along, to get along" at some critical point and some have been LUCKY while others have tragically left a big smoking hole in the ground and, more importantly, left their families in a state of despair that can only go with the loss of you. The air medical industry is very good at memorials - and that is BAD. Period.
Be sure - the risks are real and the rewards few. After all, it is just a way of getting to point A to point B. Sure, it's cool at times - but it is just transport. 60-80%+ of your flights (depending on time of year and mission profile of your service/base) will be interfacility. Not "exciting" like trauma - but, they can be challenging (more so IMHO) as trauma is a surgical disease and is far more cookbook than other call types.
I think the most vital parts of preparation are: - rock solid clinical and assessment skills AND - the ability to improvise and critically think. The fact is --- they could hire a well trained money to perform technical clinical skills - the difference is my knowing the WHY or WHY-NOT of the decision behind any clinical skill and that I have sound reasoning in clinical decision making. Accountability is enhanced and you MUST have a well developed sense of self-reliance. I like to say - THEY PAY ALONG WITH A PARTNER ME TO MAKE A GOOD DECISION IN A BAD SET OF CIRCUMSTANCES. Period. So, to that end - if you think you are ready and can step up and "be the guy/gal" - then that box gets checked off as READY.
You seem to have the requisite experience on paper and that is necessary. Only you know if you (and your family) are willing to accept the risks of this type job - so, that box may require some family input before you can decide that it can or cannot be checked.
As for interview prep - there is little I could add other than to check the excellent threads on the same topic here and on flightweb.com
On FW search Mike Mimms posts on prep and interview (I think you have to register to use search function) - there is nothing to add other than my rumblings here. Think it through - yes, it can have its rewards, but.... There are risks and they are real. And killed may not be the worst thing that could happen to you - a few have lived through crashes with varying degrees of serious damage and disability. If during a interview you are told that "we are safe, it can't happen here" - RUN. You life will depend on it.
Remember it is JUST A JOB. GOOD LUCK with whatever you decide.