207's / 205's
I have run both. 207's get about 25% less mileage than 205's, but the 205's are noticeably less sticky. Depending on the kind of riding I'm doing I usually get 4,500 to 5,000 miles out of a set of 207's (without actually running them to cords) and therefore think that either one should make the trip, but... I would consider the kind of riding that you will be doing on the trip and also be honest with yourself about how extreme you ride twisties anyway. If not too extreme, the 205's should do it without a problem and would probably be your best choice of tire anyway. If you do get a little extreme, chances are you will have to compromise something no matter which way you go. If you are running a lot of straight roads, the 205's are probably the choice but really aren't as sticky when you get to the twisty stuff. On power, the back can slide much sooner coming off of the corners and in general, just aren't as sticky so they don't give the extra margin that you might wish you had if you get in to one a little too hot. On the other hand, the 207's will wear square quicker if you're running a lot of straight roads or Interstate and a squared up 207 will not do any better (and maybe worse) than a round 205 in the twisties. (A squared up 205 is worse but will not square as quickly.) Also, the 4500 (low end) of the mileage range on the 207's is with mostly pretty hot two lane twisty stuff so if your trip is all that type of riding, you may wear out before to get home. The 205's would make it but won't stick as well on the extreme stuff so you will have to back off a little on your riding style. Do you see the dilemna? You may be able to plan your trip to work around this though.
I recently did exactly that. I live in Pittsburgh, Pa. area and planned a trip that included Deal's Gap,Tn. at one end and Ithaca N.Y.(Finger Lakes region), to meet and ride with my sister, on the other end. The head end of the trip (3500 +/-)was all two lane, mild to extreme twisties, through the mountains of W.Va., Va., N.C., and Tn. The tail end (2000 +/-)was from Tn. to N.Y. and back to Pgh. all on relatively straight roads or Interstate. I had 207's on the bike. The head end was a blast and was all quick paced, to corner pounding hard, that used the tires reasonably consistent without wearing them square, giving the best traction and not requiring any riding style compromise due to stickiness. The last two days of that leg of the trip was in the Deal's Gap area where you can just torture the tires and by the end of that, the real stickiness of the tire was pretty well cooked out anyway but it didn't matter because the second leg was all straight from Tn. to N.Y. and back to Pgh. By the time I arrived home the tires had about 5,500 miles on them, the rear was squared, but no compromise in the ride had been required. Another thing about straight highway riding is that you actually get a little better tire life, even though you wear it square, because you're not constantly accelerating and braking. That left me with minimally sufficient tred groove to not panic when the return ride from N.Y. to Pgh. had to be done in the rain.
I know this isn't a pat answer but I hope it helps you to sort it out for yourself.
[Edited by Dad on 11-05-2000 at 09:52 PM]