Learn to fly an ultra light, easy to upgrade to other air craft except rotary. Remember all aircraft are left FULLY fueled to avoid condensate in the gas. and they have pitiful locks on them any screwdriver and you are in, not like they get stolen in these times as you cant sell one without all the paperwork and tags. Most private fixed wings are non electrical in nature alot of planes from the 60s still around.
double shifting is a interesting skill as well as being able to judge gear for steep hills, or it may be better walking for some, you cant simply brake your way out of a steep hill with a loaded air brake semi. You will melt the brakes and still not stop.
as for a quiet form of transport, you can get well muffled enduros motor bikes and have a few sets of tires and a side car. Harleys as nice as they are are older ones you spend alot fixing time, Newer ones you can ride all the time but mainly electronic controlled ignition and injection so useless in emp.
problem is that you have 0 protection from elements.
as for blockages on hwy think tow truck/ ambulance for those in snow area plow truck will remove most parked cars if you dont care about insurance issues
you can always go by rail, modern diesel electrics might not work but we have a local steam coal fire one that can use normal tracks locally. and an old two man pump jack if you really need to
sail boats are good in some regions that is one area i can do ok in good weather but no way in heavy storm.
air is first way to leave no traffic jams lots of rural landing strips and you go as the crow flies cutting days of travel. second is by water if you can get to where you want by that form, third is by land as every body will be trying that.
as for being unobserved a plane is damn hard to spot after 2000 feet hell at air port try seeing more than 5 planes, most have 20+ in the tower area.