VA vs Medicare. As a VN Vet, with no disability, I don't get much from VA benefits anymore; no free healthcare. Can I still use the VA?

As far as VA healthcare, as has been said by others, update your financial information with your VA health facility. They are the only ones who can determine your status.
I asked about combat decorations because they give you an edge in submitting claims for things like hearing loss or tinnitus (constant ringing in the ears) to the Veterans Benefits Administration (which is separate from VA healthcare). You can still make a disability claim for any medical condition that was incurred on or aggravated by active duty, but after 1 year from discharge the threshold is different. You must show evidence (for instance that your were treated for something on active duty but never filed a claim for it) in your SMR's or Private Medical records within that one year period that shows the conditions at the time of discharge would have been rated by VA at the 10% level.
You can apply for a non-service connected pension that is income based if you served during a period of war (doesn't matter if you were not in combat) and you are over 65. It takes your income and net worth into account, but also your unreimbursed medical expense can be used to knock down your countable income. Also if you get ANY amount from VA NSC Pension, you are then fully eligible for VA Healthcare (possible copays).
The other possible benefit is the Home Loan Guarantee.
You can read up on all this at VA.Gov, ask questions under the contact tab or call [login to see] for q's.

Revisit the issue with VA. When Obamacare was pushing everyone into some kind of government plan I was proactively contacted by VA inviting me to apply. It never had occurred to me before...(?). In any event, I didn't want to have to pay the Ocare penalty so I signed up; best decision I ever made. All of my primary care is with VA and have never used Medicare! So, my advice is to apply right away. If you want discuss more just to settle your mind, find a VFW or American Legion VSO (Veteran Service Officer) and ask them. But by all means, no matter what anyone says, apply to the VA. As has been mentioned, there is a means test, so if you are well-off your co-pay, etc., may be more. Good luck!

I recommend stopping in at you closest VA Health Facility and having this conversation with the Eligibility Clerks there. They (or their supervisor) should be able to give you a clear picture of where you stand. Do you have a CIB or other combat decorations?