If the zeal along the route is low, the long route is pointless. To raise the zeal you need imams. Which means you need to build a grand mosque. At present your best approach would be to create the jihad, add extra troops to it, and get it to the target as quickly as possible. When the Jihad gains the province and is a success your faction leader will gain influence and piety. Also you'll be paying the upkeep of all of those units that were in the Jihad, which is worth bearing in mind. If it fails, the faction leader loses influence and the loyalty of the generals. When this occurs civil war is a real possibility. Sending two or more jihads at the same province is a tactic commonly referred to as "jihad spamming". You can quite easily create a lot of jihad markers and send them to recapture 1 province, boosting your leader's influence massively in the process. This is a very cheesy tactic and best avoided, as it can make the game unchallenging and boring.