Newbie Bitcoin / Altcoin questions

So,

Im interested in mining some crypto currencies, I currently own some bitcoin like most people on here Im sure.

Anyway, I thought about just running nicehash to mine whatever was best and then convert to BTC automatically but according to whattomine.com there are usually other currencies which are better to mine
than nicehash with my hardware.

So....keeping in mind that my primary goal is to have BTC and hold long term, can anyone assist me with these questions???....

1. If I mine some of these altcoins, for example when I originally checked GRS seemed to be the one to mine according to the site, is there an easy way to convert to BTC at some site? What sites allow you to exchange one cryptocurrency for another??

2. Today for Example, it seems that there are totally different altcoins recommended to mine currently. So I would like to mine something long term and convert to BTC along the way, something that makes sense to mine but it seems kind of pointless to mine something different everyday, like it would not be efficient and wouldn't really accumulate anything of value. Am I missing something ?

Could anyone provide me any insight into this area and how to come up with my own gameplan?

TIA