I look at the CAD render, then at the model parts pages, and there seems to be some discrepancy. There is very little depth to this model. If you can accept this, and can "greeble" it to life, then you could end up with something extraordinary. The railings shown are pictures. The model makes no provisions for railings, it is a flat surface. If would be O.K. if the railings were flat, and they had set back the walkways, but they didn't. This means much reconstruction of a model that, in my mind, is not inexpensive. You would have to make that decision. I did find a YouTube video that covers the model extensively. I do not know if you have ever designed a model, but with this model, and some of your own designs, you could make an awesome crawler. AA decision you would have to make. You change more than 10% of this model, then it becomes a model which you in essence have designed. I say this because that crawler was paid for by U.S> Taxpayer money, so anyone claiming a copyright is treading on thin ice. It is illegal to copyright something paid for by Taxpayer money. They can copyright their interpretation of it, but that is all this copyright does. You add all the walkways, and make a model, don't use their pictures, that can be made with Photoshop, or the Rendering part of any good CAD program. I write all of this because I find $16.95 expensive for what you actually get. CD's a cheap,, really cheap, and that CD is burned on a computer, not pressed, like an audio CD. So you are paying for what I hope is a pre-printed model, which isn't too bad. If it isn't pre-printed, then it is ridiculously overpriced.IMHO.
Of course,you could go here, and get a much better model, 2 versions, early and later, for FREE, much easier to add round railings to, and make seperate track links, as you have to cut the EDUCRAFT ones out also.!!
http://www.axmpaperspacescalemodels.com/CrawlerTransporter.html#.Vv9oiXqYjm1
EDUCRAFT Model: