As long as I understood the OP wants a suggestion to get a quick earning on his capital. It seems to me like he is confused about to invest directly in bitcoin or in any of the altcoin so that he get a maximum profit.
To my opinion bitcoin is the most secure investment in the entire crypto-currencies. Bitcoin is less riskier with a great potential price growth. There are few well reputed altcoins which can also be considered for the purpose of investment, they don't disappoint the investors as well.
Yes, he is confused because he's treating mining and holding separately.
If every miner saw his profits from mining after an immediate conversion, he'd never got into it. Most miners get their profits because they are getting maybe 10% after reaching ROI on top of holding it all for a whole year.