Texan, I normally fish the Lazio and Abruzzo regions, but I can tell you that fishing in Tuscany is pretty good, with some pretty well-known fisheries like the Tevere (Tiber) and Sieve tailwaters, and beautiful rivers like the Lima and Serchio. Here's the website of one of the absolute top guides in Tuscany:
I fish italy almost ever summer. there is suprisingly good dry fly fishing and some of my biggest browns have been caught there. Slovenia is great also, particularly for grayling, which italians rate higher than any other sport fish in my opinion and are not the voracious biters we have in NA. they are very difficult and technical to catch in europe.
While i havent fished the Arno in tuscany, i lived there and watched some of the biggest carp i have ever seen, some up to 70lbs maybe more.
Great go-to trout flies if you dont have time to match hatches or research the hatches there are: scud type emerger. Very small Baetis in cream, grey and brown. Adams. Tom thumb. Small black woolly buggers fished grease lined.