USPS money order should be fine ... and if you do want to wait until it cleared - make sure you let the buyer know that as well
I dont think it's a bad question, some of us really are really careful (to a fault at times), there might be things that we may have missed
and true about giving too much information to paypal ...
and this is not to rain on your parade - when you hand out checks ... there's a lot of information on that little piece of paper, too (name, bank, bank account number, signature)