Geoff and Matt,
I believe Stanley Thompson did some work there around 1950 -- there's an architectural map up in the locker room that details the work, but I've only had a chance to glance at it for a minute.
Cornish and Silva turned the par-3 14th into a 319-yard dogleg par 4, with a diabolical green (one of Dan Kelly's favorite holes).
What else remains that's identifiably Raynor? Most of it, I'm guessing, though the hills at the back of the property create a couple of holes that you might not see on other Raynor courses, especially the 500-yard second hole that plays more like 575 because it is so severely uphill. But that hole has a punchbowl green.
There's a wonderful Redan at Somerset that probably hasn't been touched -- the 185-yard fourth hole. Huge green, slopes away to the back left, easily the finest hole of its type I've played (and I don't mean that in the Gary Player way...)
The 7th hole, I believe, would fit Raynor's Alps template -- at least, it reminds me of the photos I've seen of Camargo's 7th.
The 8th is an Eden with a spine running through the middle of the wide, shallow green from front to back.
The 10th is an uphill Cape (though not a dramatic one), and one of the best holes on the course, with a green sloping sharply from back to front.
The 11th, according to Jeff Brauer (as told to Dan Kelly -- I missed this conversation by about 10 minutes, arriving late to the round) is the old Road hole, with the left greenside bunker pulled away from the green a bit.
The 12th is a downhill Biarritz of 220 yards.
If there can be said to be Short at Somerset, it is probably #17, 160 yards downhill with bunkers left and right of the green and a steep, small tiered shelf at the back of the green.
Matt, I agree with you about Interlachen. I'd play it any time, but I'd choose Somerset first. For one thing, it doesn't feel as hemmed-in by trees as Interlachen -- it relies more on the ground features to provide its test.
Maybe Jeff Brauer will step in here and contribute his observations about what remains of Raynor at Somerset. What is there, no matter who gets credit for which features, is a fine golf course.