Getting things done with the "help" of kids

I have trouble getting things done when it comes to “house/home business,” e.g. paying bills, making necessary purchases, car maintenance, booking vacation items, etc.  Some of these items have deadlines and some don’t.

An issue I have is either I am very tired after working (plus exercise on some days), coming home to a sometimes chaotic house and immediately helping my wife make dinner by taking the kids off her hands (5 and 2), then cleaning the kitchen and putting the kids down.  By the time 8 rolls around I’ve been running hard for almost 14 straight hours with no decompression time.  That time is also the best time to get the above stuff done as it is kid free.

Given I lack an office with a locking door, I am open to whichever interaction my kids want me to be in (may include screaming, throwing things, making messes, being loud, or other concentration challenging activities).  On the weekend, I’m rested but open game for such “help” and find it hard to get things done there too.  How can I better manage this?  I know my kids won’t want anything to do with me in about 8 years, and this problem will be solved (with new ones on the way), but I’m having a tough time to push through the exhaustion, or the distraction to get my business stuff done.