RedHot's diet in Vegas is primarily 91 from Costco (no ethanol) or Chevron 91 (again sans ethanol). On the road I try to find Costco, Chevron or Shell. 2200 miles in about two weeks so far and no issues.
An alternative is to consider adding an ethanol fuel treatment from time to time like STA-BIL® Ethanol Fuel Treatment and Stabilizer. I have done that when I know I am traveling through areas that predominately sell ethanol blends.In Florida we don't typically have that luxury, 99% of the stations in the SE are forced to use ethanol blends. Yet another fiasco foisted upon us by special interests (agriculture lobby).
Here's the definitive site for locating "Pure Gas" Ethanol-free gas stations in the U.S. and Canada
Note, expect to be paying almost $1.00 more PER GALLON here in FL if you insist on ethanol free gas.