Importance of temp control when "vigorous ferm." is done?

I did some searching for this, but using words like "temperature" & "fermentation", etc. brings up just about every thread in this forum

Anyway, we don't have a fermentation chamber yet (scouring for one now) and my basement is warmer than I ever remember with this brutal summer.
Right now it's 69 down there, and the ale pale temp is showing 72 and so is the tub water the fermenter is sitting in.
For our next brew I plan on using frozen water bottles and a fan to go along with the tub water and t-shirt already in use.

My question is how long do I really have to worry about keeping the temps in the 60's? We normally do 3 week primaries and then bottle. Is it OK to to just keep changing out the frozen bottles for the first 3-5 days while the vigorous fermentation is happening and then not worry about it as much? I'm not talking about 80 degree temps or anything, my basement should never get above 70.
I was thinking about ice bottles in water for the first 4-5 days, then just water and fan until the 2 week mark, then maybe letting it sit on the concrete floor for the last week.
Sound good? I can do the frozen bottle switch longer if I have to, I was just hoping to not have to keep it up for 3 weeks straight.

thanks for your help

If you are only talking about the low 70's then I wouldn't worry about the temp creep up after the bulk of the fermentation is done as the undesirable flavors are generally produced in the initial few days. So yes, keep it at your desired temp until active fermentation drops off in 3-5 days like you suggest and you will be GTG.

the off flavors you are trying to avoid by keeping the brew cool are of course generated during fermentation. the more vigorous the fermentation the more these flavors are produced. so your right you need to be most concerned during the initial vigorous fermentation. once you no longer see any signs of fermentation you can stop trying to keep it cool. you want to try to keep the temps as stable as posable but don't kill yourself trying to decide if you have added enough or to much ice.

As well, if you get too worried and you drop the temp to much you might crash the yeast...I would rather have a beer turn out a little too estery than have a beer turn out cloyingly sweet.

In the mean time, now is the time to start thinking about making a fermentation chamber as you realize how much ice bath methods can suck.

Thanks fellas - my brew buddies and I are keeping a lookout for a good deal on a used fridge or chest freezer to hook up to a temp controller. Until then, it's nice to know I really only have to concentrate on the first several days.
Thx again