Although and though, are for the most part interchangeable. The only difference is that though can also be an adverb meaning however. So for example, I can say: "This book though, is very good!" I can also say: "Last weekend though was difficult" both of which also makes grammatical sense if however is used instead of though. I can also say: "I wouldn't worry about it too much though, because most English speakers can't tell the difference". Hope this helps, Cheers!