床から出てくるのは、どうしても我慢できなくなってお手洗いに行くときだけでした。
Toko kara dete kuru no wa, dōshite mo gaman dekinakunatte otearai ni iku toki dake deshita.
The only time he got up was when he could no longer resist going to the restroom.
doushitemo - by all means, at any cost, no matter what
gaman - patience
dekiru - to be able to, to be ready, to occur
Literally,
Toko kara dete kuru no wa, dōshite mo gaman dekinakunatte otearai ni iku toki dake deshita.
Leaving his bad, no matter what became impatient only to go to the toilet.
I don't know why "doushitemo" is in the place it is, it seems to be modifying the "impatient" part rather than the "leaving bed" part. I don't know why "Toko kara dete kuru no wa" isn't negative, which would make it more like, "No matter what the cost, he didn't leave his bed, except to go to the toilet."
みんはは寝太郎をこらしめてやろうとやって来ました。
Minna wa Netarō o korashimete yarō to yatte kimashita.
The people decided to have a talk with Netaro.
What's the point of "yarou" here? "korashimeru" is a verb so why not just change it to "korashimeyou" and leave the extra "to do" out?
I'm not sure whether the "to" here is indicating speech or being used as "and then". If it's speech, then it's lacking an "itte" after the "to". If it's an "and then" then I didn't know that "to" could come after a volitional form in that way.
みんなはそれをみてこう思いました。
Minna wa sore o mite kō omoi mashita.
The people saw this and thought,
What does "kou" mean?
寝太郎はいつも干ばつのことをかんがえ、その良い方法を考えていたのです。
Netarō wa itsumo kanbatsu no koto o kangae, sono yoi hōhō o kangaete ita no desu.
Netaro had always been worried about the drought and had come up with such a good idea.
I'd just like to make sure that the translation of "kangaeru" as "worried" by the JPod101 staff was creative licence rather than an actual translation of the word. I can't find anything other than "to think".