Drafts that are trained to work are generally nice horses that adapt easily to saddle work, but be on the lookout for ANYTHING that appears to be lameness. A lot of drafts at auction pull up with foot problems more than behavior problems, namely canker. Canker is expensive to treat, not always treatable, and can take a long, LONG time to get through. Belgians can also suffer with issues like seedy toe. If you have the option to look at the horse before the auction, make ABSOLUTELY SURE the horse will willingly lift all 4 feet, because farriers won't put up with a draft that won't hold it's feet up or leans on them (and stocks are a PITA to keep around for just one horse).
A regular two-horse won't fit most drafts, unless you find one that's on the smaller side/a cross. They're too wide and too tall. A smaller one around 16 hands might fit if you take the divider out. As well, you might have trouble on the road if something that weighs anywhere from 1500-2000 lbs shifts it's weight in the trailer. Make sure your trailer and your truck can handle the weight.