Wilson is a tough, exposed, loose and remote peak that is one of the lesser climbed and more difficult of the 14ers. Most people consider Wilson one of the 3 or 4 hardest 14ers based on the hardest individual move. It is not a technical peak, but has technical terrain if you get off route. Generally as a first 14er, it would not be something I would recommend, but that is something you and your friend will have to judge based on your other experience.
You will need a helmet for this climb, its pretty loose. Wilson is much more of a climb than most of the other 14ers, especially if combining the connecting ridge with El Diente. I agree that if you have time, you may want to give an easier one a shot first, in that area, Sneffels would be the best option, perhaps go via the 3rd class south ridge, it has some loose gullies with some route finding, then a nice solid class 3 ridge. Its easier than Wilson, so a good primer to see how feel about that kind of terrain.
We did El Diente and Wilson together from Kilpacker a few years ago. The trail miles are not a problem, and the trail through the scree to the base of El Diente is pretty reasonable. Once you start climbing El Diente it gets looser towards the top the of the gully. You then have to traverse a bit below some towers (called the Organ Pipes) to get to El Diente's summit and there is some loose 3rd class involved. Back on the traverse to Wilson there is a lot of loose rock and some tricky route finding to avoid some 5th class terrain and scramble back up onto the ridge. With climbers above it can be dangerous with the threat of them kicking rocks on you. Then you have a stiff scramble back up to the ridge crest, which is exposed, there is a fun class 4 headwall. The final moves onto Mt Wilson are tough and a bit exposed as well, maybe another 1 or 2 fourth class moves. Our descent gully was pretty horribly loose, but really the best option at that point because other wise you would have to do the entire traverse in reverse. You need to retrace the ridge slightly, then down a steep series of loose scree gullies. Then you have to cross a tedious sea of loose scree in the upper basin before you link back to the climbers trail that took you to the base of El Diente.
Hope this was useful. Look through the trip reports for the traverse on this site and 14ers.com to get an idea of what to expect. Good luck, and be safe.