I finally drove a RHD car - overall, the driving part was easy. No problems with the clearances on that passenger side as I went down small alleys, etc. The lanes on the highways here are incredibly small though, and people actually drive very fast, I think traffic was going about 120kph in an 80 and there were plenty of cars, as you can imagine. I think I drove for about 4 hours yesterday. The only problems I had at first were remembering to get over to the left after making a turn,
I have only driven a RHD car once and I started in central London(waterloo) during rush hour and I had to drive to Bristol and back again.
You should try driving on the autostrada in Italy, everyone does 130-140 in bumper to bumper traffic and the speed limit is 80, it's nuts.