OK, so I've been reading the responses so far and I think a bit of clarification might be in order. First, I don't use a "death grip" on the handlebars. That's something I did on my very first ride, but I found that a "firm" grip is all that's needed to keep the handlebars from moving. The muscle soreness is actually pretty mild, but I'm concerned that if I decide to do a century ride rather than just my usual 30 mile loop, it could become much worse.
I keep my arms pretty straight, but with a slight bend at the elbows. This is the arm position I've seen in photos of other Cruzbike riders as well as in the instructional videos, and I don't find it at all tiring. I was able to hold that same arm position on my Bacchetta for over six hours, essentially steering with my shoulders, just as I do on the V20.
Changing my hand position isn't something I've tried yet, but it sounds promising. I've been keeping my hands where they need to be in case I have to brake suddenly, but I suppose on long open roads it would be safe to rest them on the hoods. Part of it also has to do with my style of riding. Rather than maintaining an even speed like most people do, my rides are more like interval training. If I see a long straight or a short hill, I'll hammer the pedals as hard as I can, and then rest. Sometimes I'll just be coasting along, and then hit it hard if another rider tries to pass me. I absolutely refuse to be passed by anyone on a diamond frame!
But those huge jumps in power output mean that my hands have to be where they can apply the most leverage, which is at the ends of the bars.
As far as keeping the front wheel straight goes, I try to completely eliminate side to side movement when pedaling. I've ridden a number of times with another Cruzbike owner, and everyone in our group noticed that he couldn't keep his front wheel straight, despite the fact that he'd been riding a V20 exclusively for years. I'm not sure that a slight front end weave is necessarily a bad thing, but it's something I try to prevent for "aesthetic" reasons.
Hopefully I'll get the V20 back from the shop this weekend so I can get some more miles in. It's now equipped with a Di2 system, which should permit one finger gear changes, making it much easier to keep a solid grip on the bars in a sprint.