What we use is flexible enough to be used any amount of time per day, although that will of course affect how quickly you move through the book. As far as I know, there are only two programs completely self-study for the student--Artes Latinae and Rosetta Stone. Of the two, I prefer Artes Latinae but it is pricey. These two are both computer-based. Most book-based curricula you need to at least learn along with the children so you can grade them effectively. I learned right along with my kids and we have done pretty well. But once you pass the first little bit when you are learning just the very basics, there will almost always be more than one way to do something, and someone needs to know something so that one can tell if an answer is really correct or not. I found the teacher helps with LitCT very good, often it would even remind me of different ways students could answer.
There are online classes available as well; most are fairly expensive. There is one list-serv I know of that has a number of free groups you can join, all translating from something or studying a book such as Wheelock's together; we tried this but it did not work well for us. We did better with the set program, even if I did need to learn a little to go along.