With the recent addition of Ore mining in KSP 1.0 long missions have gotten a whole lot easier! But I think that just refuelling isn't fun enough. I am suggesting that they should add the ability to sell ore in career mode for a little bit of extra cash. Imagine having a massive Mün base deticated to mining and have transportation landers that bring tonnes of ore to Kerbin in a blaze of glory only to sell it so you can do it all over again and even more! You could pretend you are some massive trillion dollar ore mining company. Wouldn't it be fun and usefull?