as i said earlier, spend £90 with alastair at elsemade, your seat will be transformed, no more sore butt, then for another £100 or so, you can sort out some risers for the bars, or even a renthal bar set up, you can also look out for a hard luggage set up, they come up on ebay every now and then, you can also put a flip screen on to help with wind buffeting, all these things can be taken on and off for when you want to tour. as for fuel range, it sounds like your ready to stretch your legs after 90/100 miles anyways, but if needs be, i'd carry a litre or two of spare fuel in a pannier/top box, just as a back up, you can also try and find a 19l tank.
don't give up on your bike just yet, its a good'un, if you do bite the bullet and sell it, make a point of the bikes condition being so good, after all when a bike goes beyond 30k condition is by far the most important thing, because 30k might aswell be 60k when it comes to these engines.
good luck with what ever you choose to do buddy....
