JMS, I'm currently taking turns between my '90 Hawk GT and new-to-me 2008 Versys. First impressions are that I need to do some adjusting to the Versys suspension; it's a bit harsher than the Hawk at present (my Hawk has a year-old Wilbers shock in back and Progressive front springs w/emulators up front), but I'll be checking out setup before I consider modification. I'm in Colorado, where the roads are fairly potholey and rough from too many freeze/thaw cycles. Coming from the Hawk, my power has been magically increased by nearly 50%, so it's more than adequate for my needs. I assume by the term "re-gearing" that you're thinking of the "three-tooth" mod that I'm slating for the first chain replacement, just so things don't seem so busy in the engine at 70mph+ highway speeds. Other than that, the only issue has been adjusting my clutch and throttle hands to the differing systems of the two bikes - I'm nearly there, but that first take off is still a little awkward.
Unfortunately, I'm pretty much a moto-shopping neophyte (been riding the Hawk the past 17 years), but when a friend in New Mexico found my Versys on Craigslist, I emailed the seller and got my friend to go over for a look. When he came back with a thumbs-up on the bike (and seller), I put down a ~10% deposit via Paypal and hubby and I went to get the bike the next available weekend (in early April, so we were dodging between storms) with an envelope full of the balance in cash. Had a nice dinner with my friend, the seller knew what he was doing and was quite professional, and it was a fairly nice ride home, even though we were making time on the interstate to get home before the next storm.
Being in California, I expect registering an out-of-state bike may be more hassle than it's worth, but check with your DMV ahead of time to find out what paperwork's needed to re-title, if you haven't done that before.
Good choice of "next" bike; if you're selling the Hawk, consider listing it at the Hawk GT forum, www.hawkgtforum.com