The comments on that post are worth noting. The article making that claim is from the New Zealand Herald and the alleged 700-person entourage was in the context of President Bush's visit to Sydney for the APEC summit. Obviously the security needs are MUCH higher for a US President attending an international summit than they are for a rural townhall meeting in Montana.
Another comment posted to the article alleges that "When Clinton went to Africa in 1998, he was accompanied by 1,302 people from thirteen different agencies (902 of these were military or Secret Service personnel)." There's no source given for that claim, so no way of knowing if it's valid.