Wear comfortable shoes. That's the best advice for anybody trying to navigate the area around Xcel Energy Center on foot. ¶ On the eve of the official opening of the Republican National Convention Sunday, it was easy for people without credentials to move within the no-traffic zone surrounding the arena and the adjoining RiverCentre. But getting from one side of the arena to the other is a challenge.

A St. Paul police officer working the security perimeter put it best: "If you don't have a helicopter, it's going to be pretty tough."

The police presence was heavy Sunday in downtown St. Paul. But pedestrians could come and go as they pleased -- within boundaries.

In spots, the heavy, portable fencing surrounding the Xcel is less than 50 yards from the building. But in other spots, people on foot are kept blocks away.

The most difficult maneuver is going from the core downtown area to the W. 7th Street area south of the arena.

A trip from Rice Park, where MSNBC has set up an outdoor stage, to the bars and restaurants on W. 7th would require someone to go north to 10th Street and cross over Interstate 35E to the Minnesota History Center before traveling several blocks south. Pedestrians can cross back over I-35E at Walnut Street.

In other words, a 10-minute walk is now much longer.

The presence of the security perimeter -- and the potential confusion associated with it -- is part of the reason why the Science Museum of Minnesota is closed this week. In addition, the College of St. Scholastica, which holds classes in downtown St. Paul, has given its students the week off.

Jeff Shelman • 612-673-7478