Simple answer is don't do 5 or 600 miles a day, do what you're happy with, and stay off motorways, 996's are far better on twisty roads.
Hot baths and red wine do wonders for fatigue at the end of the day.
If not, its either the ST/VFR route, but do you really want one for 1 trip a year? The ST's are miles more fun than VFR's but although i haven't suffered any probs with my ST's in the past, if you do have any worries about the reliability of a used ST and its history and that is a big concern for you then try a VFR.
Why not keep the 996, flog the Monster and have a VFR as a tourer come winter hack. Decent VFR's can be had for reasonable money.
Actually, I might be going touring in France this year, having not done it last year because of the racing. The dates don't clash with DD so I may well be going...