RE: Fall planting?
In PA - if you plan to plant the plot again in the spring - a semi-hardy oats is a good annual - like Buck forage oats - because it will grow quick and be hardy enough to handle some strong frosts - but most will die back before spring if you want to disk it up for clover.
Rye and winter wheat are good - but you might have to spray or plow it under next spring (not to big a problem to do)
FH