Well, if you're new to Drosera, you may want to practice a bit more with the easier species, such as D. capensis, D. spatulata, etc. to get a feel for how to make them happy. But if you think you've got the hang of them, then by all means give tuberous dews a shot.
As long as temps are at or below 70 degrees F, then that should be sufficiently cool. Most of the time, we keep our house temps at 60-65 F at night and 65-70 in the day. The basement stays about 5-10 degrees cooler than upstairs, so no cooling unit should be necessary unless you really crank up the heat.