Rusted spark plug ? Soak with WD40 or similar penetrant/lubricant for a coupla hours, repeating application as necessary, and then careful application of a plug wrench and a RUBBER (not metal) mallet....don't whale on it, just thud-thud-thud, and it should come loose easy enough.
As for moped law in MD, 30mph, Pedals, etc...the 93 Pacer qualifies.
You don't even need a drivers license, you can go down to MVA, fill out a law test (NO driving test) and get a moped permit for about $15.
No insurance, No emissions, No inspection required - which is why I liked having one in MD, the cagepushers get robbed on those three things.
Happy motoring, and might I suggest you print out a copy of Freds how-to-repair guide located in the RESOURCES section of this site.