I am not so sure that attending d3 college camps is the answer to getting recruited by certain D3 schools. When my son was being recruited. He played travel. He also attended several invitation only Showcases (I miss the Buckeyescout). He was recruited by many of the top D3's in Ohio and surrounding states and many further away.
None of the D3 coaches ever mentioned attending their D3 camps. In fact may dissuaded him. Later after he was helping at those same camps, he understood why. Many of the kids at those camps were not great. Many underestimated the talent to play at a D3. He did attend some D1 Camps that D3 RC's were at helping out.
When I talk to parents, many time they are targeting D3 for the wrong reasons. They are targeting D3 because they believe that is where there talent lies. Many times they are wrong. I have seen it both ways. The parents underestimated their sons talent. (I know very rare) These are usually the nicest humblest people I have ever met. Or they are over estimating their sons talent.
Many times the recruiting process will tell you were you land. For my son that was D3. He targeted Smaller, mostly Liberal Arts type schools at D1. Think Butler. Not much interest, mostly we really liked you we will be in touch. (never happened, with several). In most cases he was probably B or C on their list. He got some late interest from the Big State U's as a walk on, but he was never interested in going to a big college.
But attending the D1 camps and being seen during travel ball, even if was just enough to get him invited to a Showcase like the Buckeye Scout or Walsh Jesuit's yearly show case. Was enough for D3 coaches to see him. D3 coaches are not always waiting to pick up who is left over after D1 is complete. Many will target guys that they think may have D1 potential and are trying to find those guys who slipped through the cracks.
Now you do need to start with an honest evaluation. But aim as high as you can and the recruiting trail will tell you where you belong.
Now if you are purely an academics guy or want a smaller university close to home or you are shooting for Tufts, MIT or another academic school that is a different story. Then save your money for tutoring, baseball lessons, and Headfirst camps etc.