I usually have a problem keeping my beer cool, instead of the other way around. I'd recommend finding a place a bit warmer, so you can keep it within the appropriate temp range. And I'd recommend keeping your fermentations within the yeast's range the entire time (if possible) for the best results.
That said, I don't know if I've ever kept a brew below 70 degrees despite using some yeast that recommends it, and I recently did a saison with Wyeast 3724 (76-80 degrees), and I had a hard time keeping it that warm the whole time (it was close but definitely not that warm). All my beers have turned out just fine, and the saison might be the best I've ever made, so you don't have to be perfect, but do your best to match the recs.