VIA Marathon: all for charity, PR course, nobody gets DQ’d (though “finishers” have been known to destroy themSELVES).
These days the OLYS can ONLY be held in summer. Nothing to do with athletes, but fewest clashes with major televised sports around the world. It's all about the TV money.
Austin Texas in late March would be perfect weather. The stadium is large and the people there can organize large track meets.