How long do I have to control the temperature?

I've only got enough space in my fridge for one fermenter.
If I wanted to brew every two weeks and keep my beer in the primary for four, that means I'd only be able to keep the beer temperature controlled for the first two weeks and the second
two weeks would be at room temperature which can swing anywhere from 62 to 68 right now and would probably be 72-75 during the summer.

I've read that it's really the first 72 hours of fermentation that's really important to be temp controlled, 72 hours of lag time and then 72 hours of fermentation so giving it two weeks should be fine right?

The plan is to get a chest freezer and some corny kegs to ferment in when I have extra money and find a good enough deal but until then will this work?

After the first week I usually take my fermenters out of the chamber and place in the basement. No worries after fermentation is done.

Before I pulled it out of the temp-controlled area, I'd check the SG to make sure it's all but done.

The beer currently in there went from 1.063 to 1.020 in a week and then 1.015 the second week and I just checked it today for week three and its at 1.015 still but I just dry hopped it and I'll probably bottle this saturday.
Good to know the brew every two week thing is going work out, thanks.

I'd keep it at the recommended fermentation temperature for at least 2-weeks. Even though primary fermentation may be complete - the yeasties are still active and working to clear the beer up. If you cold crash it too early you may interrupt this cleanup process.