I'm glad that you posted this question here. Nowadays most people that drive get into driving horses after they have owned riding horses. You are totally green to both. Your goals are not impossible, but you really need to find someone to help you buy what you are looking for. If you want a riding horse, I would recommend this breeder, and they are located in Lena, close to the WI border: Appleridge Mountain Horses - Horses For Sale
I bought my KMH gelding from them. They breed sane Mountain Horses, and they start the training with the foals following their dams as they ride forest preserves adjacent to their property. They are backed and ridden as trail horses, initially, as 2yo's. They have several finished horses for sale, including a very pretty blue roan mare, that I saw as a foal in 2009.
When someone recommends a breeder/trainer, you definitely get what you pay for, so don't go cheap.
They train their horses to avoid knocking your leg into trees, which we discovered after we had bought "Long Arm of the Law."
Also, I believe that they are culling out their herd and may be out of the breeding business in a few years.
Gaited horses are VERY COMFORTABLE and a very good way to get into pleasure riding.