Not sure where to fill up, as I run normal 87/91 and the BP near me closed that had 93 and E85.
You may know this already, so sorry if you do... Just a heads up, E85 doesn't stay at 85% all winter. My dad used to haul gas for Holiday until 2019 and had explained it to me that as the temp drops the ethanol has a much harder time burning than gasoline, so they change the blend ratio as the winter goes on (similar to the #1 vs #2 diesel blend ratios in the winter) to allow it to still function in vehicles. I believe the mix ratio gets as low as E50 when its cold in end of Jan/Feb which slowly tails off back to high 70% into the spring. It may be something that the station can read on their instruments in the back office if you call/go in and ask. but you may have better luck with a stand alone sensor to check/validate their readings if your car doesn't have a flex fuel sensor installed.
This may help find stations that have E85 as well
https://afdc.energy.gov/fuels/ethanol_locations.html#/find/nearest?fuel=E85
Another more clunky alternative...
https://www.mnbiofuels.org/e85-providers