i've done a few trips on my sr500.....and so far its been great, i didn't have any issues with the rack i used (just a generic MEC one) i haven't had a need for a front rack (because i don't use front panniers) but my fork has seems to have eyelets to take one (its the 2005 model) i did beef the tires up from 25c to 28c and there was still plenty of room for fenders. One thing i might do is swap out the front chainrings for something a bit lower, the granny is still only a 30t, which wasn't bad for the terrain i was riding but might present one if you hit some really big hills. I think all in all i'm glad i picked it over one of the touring models for the sort of touring i do which is carrying minimal amounts for a short time. so far i've packed it with rear panniers (carrying the usual stuff such as clothes, rain jacket, some food) and occasionally a tent, and never had a problem. what i think its really good for are those small 2-5 day tours, when you don't need to bring everything plus the kitchen sink with you.
But to answer your question......if you just want to do 'light' touring (or midweight) then this is a great bike. The T800/T200 Trek 520 etc are great bikes for full on touring but i find the SR500/800 are much more versatile if you don't plan on cycling across the country (not that you couldn't on one i'm sure)