I learned a few things, some from advice that I didn't take. Not that I was stubborn or felt smarter than the advice-givers, but rather that I realized I needed to hurry to beat the oncoming freeze, so I took a couple shortcuts. They were:
1. I didn't affix the boards to each other.
2. I didn't lay the tarp as tight against the boards as I had hoped to, in part because of #1
3. I tried at first to use cheap tarp, and thankfully soon realized I needed something better
4. I didn't measure exactly the slope of our back yard
5. I didn't buy Rebar as my main type of support stake initially
Not too bad, as it turned out, but the errors above made the project cost a little extra and take a little extra time, but it was fun, and sometimes you just have to learn your lessons yourself.
As for being careful what I wish for, the rink has so far seen limited action, because the "early winter" has brought a lot of snowy days and too-cold-to-skate days for the little Mites in our family. But it's been a blast so far, and a hit with others as well.
Lastly, my sons' skating and playing skills have improved dramatically. They may last longer in the sport of hockey than I originally speculated. One thing I've read about practice time seems to be true: small areas for hockey practice are ideal for learning the game. Our rink is 22' x 32', which is good for their ages, but will likely have to increase slightly for next year's version.
One unexpected pleasure of the rink: the homemade, hand-held Zamboni is a lot of fun to use!