I'd try not to fall in the trap of ..well we live close now, we can spend every single day together! I would be intentional about any change in increasing time, and make sure everybody was on the same page, and if you start spending more time together, have a check in a month or two in to see if it's still working for everybody. I'd probably slowly ramp up the time together, even if you want to spend tons of time together, so if I reached a saturation limit for togetherness, I'd find it easier to recognize (don't think most people work like me though)
You mention there will be more couples time opportunities, I'd just have a discussion with everybody addressing the fact that if suddenly one of the couples starts spending a lot more time together, and it causes a problem/imbalance in anything, such as "you two spend all this time together and I feel bad that my other partner doesn't want to spend as much time with me" that everybody knows they are encouraged to speak up. If everybody knows problems are possible, it can make it much easier to speak up if a problem occurs.
Regular group meetings seem to work for a lot of people to stem off any issues.
Most of this isn't relevant because you aren't moving in together, but I do think some of the points might be useful to go over. http://www.lovemore.com/articles/plstyle.php