Billy,
Sideseam Leggings are quite easy to make. Trust me if I can make them anyone can. One of Mark Baker's Pioneering Videos has a excellent demonstration of making them. He also demonstrates making them in one of his "Pilgrims Journey" Books. A pair of leg ties wrapped around just bellow the knee will help keep them up. I have a pair of wool ones for Winter and a pair of deerskin ones for warmer weather. They can be worn with a breechclout or with britches. The length depends on what type of shirt you may wear and whether you will wear a breehclout or britches.
Centerseam Moccasins are not all that hard to make. I made a pair from Buffalo and like I said before if I can do it just about Anyone can. There is all kinds of info on the Internet about making Centerseam Mocs or even buying a pair already made.
Take care,
Brian