The Principality of Monaco is a city-state in Western Europe. That's a small wealthy town on the seashore. There's probably not very much to do for the kind of people that are this wiki's audience, except walking in the old city and in the center and a couple of museums (especially the famous 'Musée Océanographique' if you're interested in sealife). One day is usually more than enough. Really overcrowded in August.
Leaving the city
Dont expect to hitch out there, take a train to Nice (or Saint Laurent du Var if you're going to hitch westwards) or to Ventimiglia if you go east. Another, cheaper solution is the bus TAM 100, going from Nice to Menton on the italian border, the fare is 1,30 € regardless of the distance. It stops at Place des Armes.