you might want to check into the availability of part time jobs in that area before you go to the trouble of a refresher course or school. they're few and far between, usually because once a company outlays a significant amount of money for the truck, insurance, and taxes they need to recoup as much as possible. that means miles and time.
check into some of the contract mail carriers. one is
MCA that is always hiring for part time or casual work. apply even if there isn't an opening, see if they call you and then explain your situation. think of it as a cheap way of finding out what they think.
hth