Eric -- best way to get an idea of prices would be to look at
CycleTrader. You can search by the area you intend to buy in and get an idea of what's available, price, condition, etc.
Now, for the bad news (possibly). I'm not sure what you're wanting to do is even possible. I'm not aware of any state where you can register and tag a vehicle unless you are a resident of that state or unless you are a member of the U.S. military stationed in that state. My best suggestion is to decide where you're going to land and contact that state's motor vehicle department and see if there's any way to accomplish what you are trying to do.
Even if you can work around the registration problem, then you'll have to tackle getting insurance. Again, may be a problem for a non-resident only here for a temporary vacation.
In all honesty, your best bet may be to arrange to rent a bike for your trip. If you rent, make sure you check into mileage costs as you're looking at putting some serious mileage on a rental. I don't know what transportation costs back to Australia would add to the cost of any bike you bought here, but on one that old it may be more than the cost of the bike.
I haven't been to the other states you mention, but I've been to Colorado and Wyoming several times. You mention your trip in "early 2012". If possible, you need to make your plans to not hit the mountains before June 1st. Some of the mountain passes still have snow and may be closed prior to that time.
In Colorado, a few places I suggest are (click on links for more info):
Mt. Evans -- Just west of Denver. Highest paved road in North America. Over 14,000 feet. Road closes form late Sept. to late May.
Cripple Creek, CO -- Tourist area but lots of interesting sights.
Royal Gorge -- Breathtaking. I consider this one a must see although if you go to the
Grand Canyon area first, Royal Gorge may seem like a ditch.
Denver Museum of Natural History -- If you like things like this, this is a good choice.
Here's a good web site that may give you some suggestions on scenic areas to ride through. Most roads through the western 2/3 of Colorado will give you your daily dose of the twistys.
The only two places I'd suggest avoiding are Vail and Aspen. Too many high-society types for an old country boy like me. If you don't fly in in a Learjet, you pretty much get the cold shoulder. At least that was our experience.
Wyoming is just gorgeous. Some beautiful mountains in the
Jackson Hole area. You could probably spend your entire time in
Yellowstone and still not see it all. If you want to stay right in Yellowstone, park facilities are run by
this company. I'd suggest making your reservations early. If you don't want to stay in the park,
Cody, WY is where we usually stay. It's about 50 miles east of the east entrance to Yellowstone but is about the closest area to stay other than the park itself plus Cody has plenty of attractions all it's own. There's a guy over on
Gold Wing Facts that is planning a trip to Yellowstone and there are some tips from members and lots of great photos in the thread.
If you wanted to go into eastern WY,
Devil's Tower is pretty impressive but it's all out by itself and a long trip just to see it. If you were to go that far, I'm not sure I wouldn't go ahead and make the ride down to
Mt. Rushmore. I still find the night lighting ceremony gives me goosebumps but maybe that's just an American thing.
Just one word of warning. Watch out for critters. The mountain areas are full of deer, elk, antelope, etc. Inside of Yellowstone,
can be real interesting.
You have an amazing adventure in front of you. Best of luck on your plans.
Hoss
