The different ways to translate "when"

This is more an observation on English, than Japanese, but the word "when" is used in quite a few different ways. And I’ve been wondering how to translate these different meanings into Japanese.

"when" as a conditional:

I will do it, when I can.

Here, "when" acts mostly as a conditional, with

I will do it, if I can.

having a very similar meaning. Though there is some difference in meaning, and that’s what gives me trouble. How would one translate these sentences, and especially the nuance between them, into Japanese?

"when" to give a time point context:

When you come over, I will give it to you.

Here "when" provides a time context, specifically an approximate time point, at which the second phrase occurs. Would using 「ときに」 be correct here? What about 「時は」or a conditional？

"when" to give a times span context:

When you visit, we will visit lots of places.

Here the "when" phrase does not specify a time point, but rather an extended time span. A more sensible term would be "while", though for some reason that’s not how one says it in English.

I think the way to translate this is using「間」, is that correct? What would be the difference between 「間に」 and 「間は」, would be also possible to express this using a conditional?

"when(ever)":

When I go to school, I bring an umbrella.

I’m not sure whether this is always an contraction of "whenever", but in any case, how would I translate this kind of "when", where not one specific point in time is meant, but rather a general, conditional time point that might happen never or many times? I’ve seen 「時はいつも」, 「conditional+いつも」and a plain conditional in this kind of sentence, but I’m not sure what the different nuance of each is.

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If my categorisation is unhelpful or unfitting, alternatively, I would like to ask about the meaning and usage of 「時に/は」「間に/は」, and, in particular, when to use them and when to use some conditional.