If you want to have a couple glasses of wine or a cocktail, it should be okay if you skip that evening's dose. I wouldn't do this often. And remember that even that evening you're still going to have Klonopin in your system so drink slowly. Very slowly. If you've already taken the dose and then find yourself in a social situation, you could probably get away with hanging onto a glass of wine or even a cocktail and just taking a sip every now and then. More than that I cannot recommend.
Here's why. When I first started Klonopin I was feeling so much better I tried to go back to my old life as fast as I could. In my old life I was definitely a drinker, though not an alcoholic. Anyway I didn't skip my dose and even though I didn't drink quickly, the drink I was having was strong. It hit me like a freight train. Seriously, it was like I was taking the alcohol through an IV or something. The drunk came on much quicker than I'd ever experienced and it freaked me out.
Like Kitt said, both are CNS depressants, and both will magnify the effect of the other. When people abuse benzos and alcohol together it can be pretty bad. When I was a kid I remember people blacking out and doing some of the craziest stuff I've ever seen. I knew a girl who took a couple Xanax and drank a bottle of champagne right before having to have her stomach pumped. So never, EVER drink to excess. Better not to drink at all, really.
Benzodiazepines combined with alcohol are also very hard on the liver.
I quit all together, pretty much. Now and then I'll nurse a highball for hours on end, adding ice to it, and I don't even feel comfortable doing that.
As far as the concentration goes, that should get better the longer you're on it. Some never even have this side effect. I didn't, or maybe I just didn't notice.
Withdrawal, I've heard, isn't easy. The longer you're on Klonopin the harder it will be. But you have to weigh the bad and the good for yourself and make a decision. For me Klonopin is very effective and that's all I care about. Someday I suppose I will try to go off of it but I'll cross that bridge when I come to it.
Good luck to you.