Should I join?

The Air Force has specialties for RNs. OR, ICU, and ER are always in demand. If your rehab is inpatient rehab (like chronic trach's , neuro rehab, etc), then I would say that would count as acute care nursing (i.e. med-surg). They don't generally like nursing home type experience; get a hospital job ASAP if you're doing nursing-home type stuff.

You are salaried (not hourly), and therefore there are fewer incentives to work nights; you end up rotating back and forth every couple months.

You are typically vulnerable to deploy 6 months out of every 24 months. You can't take any family with you on these deployments and they aren't fun places. I think six 12-hour shifts per week on deployments would be a reasonable expectation, but it varies.

You can't retire without 20 years or more of service. You can separate honorably as long as you stay out of trouble, pass your PT tests, and fulfill your commitment. You typically sign up for a 3, 4, or 6 year contract at a time. You can't just leave in the middle of your 4 years because you suddenly decide you want to reenact '19 kids and counting.'

You should only apply to join (it's a competitive application) if you have a desire/willingness to frequently move/travel coupled with a willingness to serve. People who join the military for loan repayment or because they think they are going to join Seal Team 6 are rarely happy.