Yes, bill of sale, limited power of attorney, some pictures of the car - and a check - and you're all set. What year is the car? Older cars are easier.
I used this place:
http://www.getnewtitle.com/
In a nut shell- it's easier to register cars in some states than others. In Maine they don't issue titles for cars before some year or other. So you don't need one to register the car. Ah, but if you live there and have no title, then move to another state, the other state has to accept your registration as a title. You register your car normally, using the Maine registration as a title, you get new plates and a new title. It's silly and a PITA, but it does work.
They can do it for newer cars too, but I don't know how that works. Probably something similar, but it costs more. You're thinking kind of like I did. I almost certainly could have gotten it resolved without the cost. I know what happened and I know where the title was lost. But the time and effort to get it done that way wasn't worth it for me. I just wanted it done and legal. If I hadn't gone that route, I might still be dealing with it instead of enjoying the car and building my project.
What ticked me off was how unwilling my own state was to help me with the problem. I bought the car in CA and the CA DMV was great. They would have sorted it out eventually, but it would have been a lot of work, especially with Colorado fighting me every step of the way. It was really, really clear what happened and who was responsible. Seems there should be some way to resolve those things for the citizens who pay the taxes, but there isn't, at least here.