Just joining (Associate) is easy. This basically allows you to use the various guild chapters as a place to stay and have friends.
I recommend not staying at the Skingrad guildhall however. Unless you
like the idea of waking up to find http://www.uesp.net/wiki/Oblivion:Vigge_the_Cautious next to you in bed!
On a serious note, you can also get the enchanting and spellmaking altars from the Frostcrag Spire DLC. If you play on a computer, you can simply use console commands for both. That is how I do it.