I've build 5 rods since last year, including a fly rod that I bought as a kit from Cabelas. The kits I've bought have been very good, the only part of the kit I don't use is the rod finish. For me the toughest part of the rod buiding is in the set up and getting the handle bored out to the correct size. The wrapping of the eyes is easy. (Don't make my mistake and get in a hurry though.)

The toughest part is rod drying if you don't have a rod dryer. If you use a slow drying finish, like flex coat high build (which is what I use) you have slowly turn the rod for until the expoy hardens. (I bought a rod dryer after my 2nd rod.)

Good luck