Christendom had got too many bad news for centuries. Muslim conquest, dhimmitude, lost territories, persecuted churches. Arabia Petra, Levant, Jerusalem, Syria, North Africa, Sicily, Crete, Spain, all lost, eastern, western and heretics alike. Rampant piracy and slave taking raids. A Muslim base in south France for 80 years (Fraxinetum). Too much. Plus, Vikings and Baltic Slavic Pagan raids, the Great Heathen Army, etc.

Then Manzikert, and the Eastern Empire was itself in danger. Plus, some important symbolic churches in the holy land were destroyed by a zealous sultan. What could the Pope do?

Some good news were coming: Some french nobles (mostly non-primogenit sons that would not inherit any land, and so could only hope to be governors or advisors for their titled fathers and brothers) decided to go to Iberia with a bunch of knights and kick some Muslim ass. The Iberian kings consented and even granted titles to some successful helpers. The Pope sent his blessings.

The best example is Henry of Burgundy, who thought that being a Count under the king of Leon, ruling over lands captured from the Muslims, was better than being just the brother of the Duke of Burgundy. His grandson afterwards thought that declaring himself to be an independent king (Portugal) was even nicer, but this would be after the crusades.

The popes were too used to kings which would fight each other, drink, hunt and ignore the larger peril just because it did not threaten them immediately. Or, that would be afraid of leaving their lands to fight, lest their enemies attack them. 

Suddenly, there were instances of successful cooperation, over large distances (France->Iberia). Finally some results! 

So, Pope in 109X just went to france to give this example a very strong push to generalize it!! Make the nobles swear to help. Make them swear to keep peace while their neighbor is away crusading. Find someone to coordinate their efforts and financing. Make them understand that if they do not work together they may fall one by one.

I do not know what do you mean by 'peaceful'. Even the crazed children or peasant crusades did not hope to win without fighting

The only instances of peaceful "crusade" I know come from the Franciscans:

St Francis, who went behind the crusader lines directly to the Sultan tent, trying to convert the Sultan himself (and the Sultan just expelled him back). 

Ramon Lull, who considered the Muslims just a strong christian heresy, even if more distant than previous heresies (a position with many valid points) and wanted to convert them by preaching. He studied for many years, even convinced Universities to study Arabic to help the conversion of Muslims, and went himself to Tunis - from where he was banished after debating theology with Imams in Arabic
He was beheaded on his third preaching trip, when he was 80+ y old.

The Franciscans also made other direct attempts to convert Muslims in North Africa. The five martyrs of Morocco are maybe the most known example, they are buried in Santa Cruz Church at Coimbra. They just went straight to Morocco to preach publicly. Portuguese merchants and mercenaries advised them to stop, before the inevitable execution happened. This was 1210, contemporary with the crusades.

But I do not think they would call these conversion efforts as "Crusades".
Besides, Ramon Lull is at the end of c XIII, it may be considered after the crusades time.  

BTW, these Franciscan efforts are directly related with them being granted custody of the christian holy places by future sultans

(and I am not giving direct references as you can easily google the names)