To use your VA benefits, you would need to access care at a VA facility. Medicare does not pay for services rendered at a VA facility.
However, if there is not a VA facility where you are, then you are on Medicare Part A (hospital) and Part B (outpatient) only, which means under Part A you would incur a $1,288* copay during the first 60 days of a non-VA hospitalization; thereafter there are copays of $322*/day (days 61-90) and $644*/day (days 91 and thereafter). In a non-VA skilled nursing facility, you would start incurring a daily co-charge of $161*/day beginning with day 21-100. Accessing any outpatient services would result in needing to meet the annual Part B deductible as well as incurring the 20% of the assignment charge not covered by Medicare as well as any potential excess charges (which cannot exceed 15% of Medicare assignment). Lastly, unless you are able to obtain your drugs thru the VA, you would not have prescription drug coverage under Medicare unless you had either a stand-alone drug plan or a Medicare advantage/HMO that includes a drug benefit.
*Note: the copay amounts above are based on year 2016.