Your story is unique with the VA, and the VA isn't any different than any other healthcare system. You state you had gone to the VA Outpatient Care facility in your area. Not sure that you had an appointment, but they usually won't see anyone w/o one. The VA hospital is different and won't turn any veteran away. VA will tell you to go to the VA hospital over a clinic whenever you feel something is critical. Walk in to a clinic with obvious acute chest pain and they'll tell you to get in an ambulance and go to the nearest hospital (I've witnessed this scenario while at my CBOC).
Getting pre-approval paperwork from them (as you did) eliminates the unclear from their documents judgement/approvals after you've incurred some serious hospital emergency bills. A lot of the documents from the Va (and there are many) address everyone connected with the VA. This is veterans of all types of service, from 2 years and out - to career retired and on Tricare. Add to this those who left relatively unscarred to those mentally/physically scarred for life, and you can see why it's so complicated.
I've been with the VA for quite awhile now, and appreciate everything they've done for me over the years at little to no cost out of pocket. When evaluating the ACA and this scenario, I elected to stay with the VA and pay for ACA coverage (with no available subsidy) as a just in case. I figured that it would start paying back to me (financially) on Medicare, staying with the VA and traditional Medicare coverage - and it has...
If one chooses to leave the VA for ACA coverage, there's no guarantee you'll be accepted back when you go on Medicare or just decide to return (they do state that you'll have to reapply and be accepted). If you stay with the VA, you have to really look at this area of concern with their non-service related coverage at non-VA facilities under the age of Medicare coverage. This was the reason I stated it's my catch 22 scenario - staying with VA leaves one vulnerable to emergency coverage judgement, and ACA coverage to insure against this area of concern doesn't allow any subsidy. Getting a subsidy requires a veteran to leave the VA.
FYI - since you are more than 40 miles from your nearest VA hospital, the local CBOC probably has a SOP in place to provide pre-approval paperwork
for the local hospital. The 2014 Veterans Choice Policy allows them to do this along with if you have to wait more than 30 days to see a doctor.