Matt,
I think I could help a little, having played/designed one, and toured the other just prior to completion, without playing. Of course, thats because I spoke with some gentleman who have played both in Kansas senior competitions.
You know where to find me......
Cottonwood has been discussed here. My comments are that it is Nick Faldo hard - he has some double fw where I would only put one. There are a few blind shots (watch the pond on 10) and some say the cousre is too formal looking for the sand hills (a cut stone wall, fake stream, etc.) There are some really dramatic holes right now, but if the housing ever takes hold, it will diminish in visual quality.
SCS is a flat site, with many railroads nearby, and in housing. To compensate, I used a lot of man made design features - there is a version of the Alps, Road Hole (as its original par 5 version), Redan, etc. Only a few holes are treed - 1, 2, 9 and parts of 11. The 9th has a postage stamp green inspired by Ross at Detroit, the 18th is an homage to RTJ fw LZ bunkering and the 4th is a sideways biaritz. The 15th has a centerline fw bunker and a Mae West green, again, all manufactured.
The biggest negatives I have heard is the 10th - long par 5 into the wind. It stems from my KN days, when they submitted an ideal hole concept to GW magazine. That was a double DL par 5 with water left then water right. I never had the op to build one, and needed two detention ponds there to accomodate housing so I figured what the heck. The green is also very KNish, kind of like 18 at Kemper Lakes. Its hard, and doesn't seem to fit the rest of the course.
As a result, and also because the houses aren't built everywhere, you might find it great fun to play. In any case, for $40 or less its a great value course.
Of interest to both Cottonwood Hills and Sand Creek is that the water table is only a few feet below the surface, which affected the design of both. SCS doesn't have sandy soils like Cottonwood does, as its 30 miles east, or so.
BTW, according to Golfweek, SCS is now second in KS public courses. Colbert Hills is No.1. If I recall, you have already seen that one. I like Alvamar, but I think (bias may show) that Colbert has more challenge and scenery, and Sand Creek has more design variety.