Showcases are a good way to be seen by a lot of coaches in one place. At camps you are being seen by one coaching staff. I recommend a mix of the two.
When you start the recruiting process make a list of 20 schools your DD would consider attending. 5 dream schools, 10 good choices, 5 fall back plans. Be flexible as your list will change as you go through the recruiting process. Try to attend as many camps on the list as time and money will allow. It also helps to follow goldfastpitch to see which players have verballed to schools in your top 20. If your DD is a pitcher any school that has already verballed a pitcher in the same class as your DD should move down the list while schools who have not verballed a pitcher that year should move up.
If a coach personally invites you to their camp you should strongly consider attending, but beware of blast emails and fliers and those are sent out by the thousands to fill spots.