It is easiest to get them to seat with a compressor. My LBS does it for free for me, although I do always offer to pay for the Stan's. As far as a flat, you probably won't have one but if you do you have to remove the core and stick a tube in. My husband had one and he said it was way simpler than he anticipated. He is not very mechanically inclined. Knock on wood I haven't had it happen yet.
The one thing you do need to watch is Stan's will dry up or form little solid masses that look like coral. If this happens you will not have the level of protection. I didn't know about this until I rode a 27 mile race with a really soft rear wheel because it wouldn't hold pressure. Let's just say 20 PSI on a 26er and a rooty course is not a good set up! It is variable with weather, this summer I have had to add Stan's after about 1.5 months. In the past I could go 4-6 months. I ride for the LBS sponsored team so they happily check it for free and knowing we bring them good beer or homemade cookies now and then. 
On the bars, I cut mine down twice. Wider bars help on the 29er so we cut quite a bit off at the fit but then I rode for awhile and decided to cut them so more. I am not sure how much but now I am in a happy place.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan