Info on the net says to stop at the Visitor Center to purchase tickets for visiting Cliff Palace, Balcony House, or Long House - one of my questions is how does the ticketing work. Do they sell out, are they sold by time, i.e. 10 o'clock is sold out next available is 4PM?
Which tour do you recommend?
Is there a difference between the $2 ranger led tours and the bus tour for more?
What can you see on your own and is it worth it, without a guide?

Any of the three, or I should say ALL of the three, are worth it, but ONLY if you have some appreciation of what you are seeing. The guided tours are done by Ranger Naturalists who know their stuff. Some of them have been there 10 seasons or more.
Balcony House is the fun one to me because you get to climb tall ladders, crawl on your hands and knees, and sit on the dirt like the original dwellers did. (I hope the ladder climb is still there.)
Long House, too, is intersting as is Cliff Palace. You cannot go wrong.
Sure the tickets sell out; our parks are being loved to death, which is why the ticket system had to be used. The idea is to get there the day before and buy your tickets. On arrival day, you tour the sites that do not require a ticket and prepare yourself by studying the exhibits in the Visitor Center.

Don't want to do that? OK. Why are you there?

You can see much of Mesa Verde on your own, but you aren't allowed to visit cliff dwellings without a ranger present. The ranger tours are interesting and informative, well worth the money.

We've been able to get tickets for a tour beginning in the next 1 to 2 hours any time we've tried. Earlier in the day is better.

I liked Balcony House best, and I think kids would like the crawling around. Cliff House is the most famous. I think Long House would have fewer visitors, because, as I recall, it's more out of the way, and it's in the middle of the area that was burned in 2000.

I don't know anything about the bus tours, but I like to go at my own pace. A day or two is about right for a thorough visit, but you can get a good feel for the place in a long half day.

ttt

We took a bus tour when we were there a couple of years ago, and thought that it was very worthwhile. Our guide gave us lots of information about the history and culture of the ancient inhabitants, theories about their abandoment of the site (most likely - drought), more recent history, wildlife, flora and fauna, and geology of the area. We learned so much more and were therefore able to appreciate what we were seeing than if we had tried to tour it on our own. Also, I'm sure we got a much broader overview than we would have gotten only from the ranger tours of the specific sites that one buys tickets for. Mesa Verde is fascinating and beautiful, I'm sure you'll love it.