Petersen Mogas STC on my C182/O470R as well. No Pb fouling, not had any issues at all in over 3000 hours and one overhaul. Around here, you have to buy 91 Octane, it's readily available price range between $3.20 and $4.00 /gal. I do test for ETOH and have never found any in labeled ETOH free fuel. There are many snowmobiles and boats that keep the ETOH volumes flowing here as well as aircraft, although the station nearest my base was recently sold to a well known E85 peddler who immediately discontinued ETOH-free fuel. I tested his E85 and found the alcohol level was consistently 93% which makes for a good cleaning fluid but nothing I'd put in an internal combustion engine.
I will continue using Mogas even if the FBO comes up with a lead free avgas that requires an STC on principle alone. I don't know if GAMI says it can be mixed with mogas. I am able to use SwiftFuel UL94 without an STC, but according to Swift if I want to use their 100R I would need to get their STC. They are offering a "forever STC" for any future fuels they may have, including 100R, for $103.00. I am undecided whether I will buy the STC or not, since I don't need it now, but I do wonder about on the road fuel availability.
As for transferring fuel, I started with 6 gallon cans, then bought a DOT certified gas tank permanently mounted and bonded to the truck bed. It works pretty well. A buddy who has a C182 like mine went a different route and bought a used semi-tractor 100 gallon tank and put it on rails in his truck so he could remove it if he wanted to use the truck as a truck, put in a Tutthill 12V pump, hose and nozzle.