Getting to Liechtenstein:
Liechtenstein is centrally located to all of Central Europe, and though it has neither an airport nor direct train service from other nations, it is easy to reach.
Liechtenstein and Switzerland have a shared customs agreement, so no passport or customs controls are conducted between the two. Swiss customs manages the border crossing to Austria at Feldkirch on behalf of Liechtenstein.
Once you're there:
During the convention, Worldcon will be running its own supplemental bus system to provide rapid and timely service to all function spaces and most lodgings. The low-floor buses will offer easy access to all members. The bus schedule will be optimized to minimize the time required to get between panels, such that everyone has a chance to enjoy the entire schedule of events. Reduced evening and overnight service will allow members to party as late as desired and still make it back to their lodgings; however, those staying in group lodging are requested to obey noise curfews when returning late.
Before and after the convention, Liechtenstein Bus will provide inexpensive service between all the communities of Liechtenstein and the bordering towns in Austria and Switzerland.
In all cases, we would like to discourage Worldcon members from renting cars. Liechtenstein is a small country, and if cars are driven from function space to function space during the day, traffic congestion and full parking areas are likely to frustrate all attendees -- those who are driving the cars stuck in traffic, and those riding the buses behind them.