Central American diplomats Wednesday reached an agreement in principle for U.N. peacekeepers to patrol Central America to make sure guerrillas do not launch cross-border raids. The U.N.'s working document for the force called for up to 100 military observers to monitor Central American border areas in speedboats, helicopters and all-terrain vehicles. Military officers and foreign ministry officials from Nicaragua, El Salvador, Honduras, Costa Rica and Guatemala reached agreement in principle to recommend the plan Wednesday.