Curse of Strahd is the 5th Edition Ravenloft product. It's a little different from the 3.5 stuff, from what I remember. That aside, porting it to 3.5's rules wouldn't be difficult. It would mostly be a matter of redoing all the stats and abilities on the characters/npcs/monsters, and adjusting the skills wording in the handouts that contain the adventure (though you could really do that on the fly as you're the only one seeing it). Castle Ravenloft, if I remember correctly, is the same as in 3.5 Ravenloft. Also, this version has isometric and cartesian maps.