Thank you:)

I think “当…时候” is similar to "when". Example: What do you eat when you are hungry? 当你肚子饿的时候，你会吃什么？

But organizing a trip like this, is not so easy. 但是组织一次这样的出游并不是那么容易。 Firstly I must contact all the scouts and their families, and organizing the rides is very difficult, because cars are never enough for everybody. 首先，我必需联系所有童子军和他们的家长，由于车辆的短缺，因此安排出游的车辆也是非常困难的。 Therefore it’s important to make sure that all the scouts bring all the necessary; A suitable clothing, mountain shoes, k-way, packed lunch, and even some object for the scout activities like the field glasses and the compass. 所以确保童子军们带齐所有必需品是很重要的：一件合适的衣服、登山鞋、雨衣 (k-way means raincoat right?)、午餐便当，甚至还有一些活动中需要用到的物品，如望远镜和指南针。 Obviously I must bring some spare object, because not all the scouts remember al the things. 显然，我（还）必需带些备用的物品，因为不是所有童子军都能记得带齐所有东西。 Despite all the works, this kind of trip is very pleasant and satisfying. 尽管大费周章，但这样的出游活动还是非常开心和如意的。 I like to see my scouts happy to be together and to be with God. 我很高兴看到我的童子军们开心地相处同时与上帝共存。 It’s a trip that they will bring in their heart for the rest of their life. (Sorry, I'm not very sure how to translate this sentence into Chinese.)

" to have to do something " : 要做… The meaning of " for something " depends on the context. 1. I have to study for exams. 为了通过考试，我要学习。 2. I have to cook for my boyfriend. 我要煮东西给我男朋友吃。 3. I have to study for 3 hours today. 我今天要花3个小时学习。