If Boldin realistically can be had for just a third round pick, you have to make the trade. Yes you are getting a receiver on the "down side" of his career, but he likely still has another 3-4 years of 1000 yard seasons. He would truly be the #1 receiver we have been looking for the past year.
I like Hartline, Bess and Camarillo but they really shouldn't be counted on to be the main target. Imagine getting Boldin and allowing those three to be the complimentary receivers that they are? Hartline would easily be the #2 target with Bess in the slot. With Boldin on the field, Bess could put up Welker numbers. I am not kidding.