To answer your question Roxanne, you need to give your horse SOME
down time -- every day riding will not allow the tendons and soft tissues the
time they need to recover after the tiny tears that occur from
exercise.
I would suggest a schedule of riding two days and giving one day
off. I'm from Kentucky, too, so I know what you're talking about with the
mud. ;) I am also only riding 5-6 miles at a time these days -- and
only twice a week. That's not enough to build much conditioning,
but at least I am maintaining condition.
Once you can start doing your longer, harder (15-20 miles)
conditioning rides, you will need more than one day of down-time between
conditioning rides.