Accoding to WikiPedia, he was trying to get to Montmedy, in Lorraine.
Even if he escapes that doesn't mean he will be able to do that much. For one thing he doesn't have finances to bulid an army up to retake the country. The nly way he would be able to do that is to convince the king of Austria that this upstart republic is a threat and give economical trades to move Austria into action.
There never was a king of Austria. It went from Archduchy to Empire under Francis II in 1804.
1790-1792, Leopold II was Archduke of Austria, Holy Roman Emperor, Grand Duke of Tuscany, King of Bohemia, and King of Hungary. He was also Marie Antoinette's brother and the guy who put down the Brabant Revolution.
OTL, he didn't help France because Russia was ready to expand (Poland and Ottoman Empire) when Austrian and Prussian attentions were elsewhere.
If Loius XVI had escaped, i think the various royalist revolts would have been stronger, especially the Vendee Rebellion(1793-1796). Maybe Vendee could have been the spark for something bigger.
http://en.wikipedia.org/wiki/Category:French_counter-revolutionaries