Go by yourself. Do not make a big deal of it with her. Take pictures of the nice areas you stay at and the things you see. quietly show them to her. You are trying to sell the experience. You are not tied together with a rope you can each do separate things if necessary.
Camp right on the beach on the Bolivar peninsula. It is permitted and the pass is very cheap. Do some surf fishing or bird (flying type) watching. It is just a short ferry ride away for you.
You need to diffuse the situation so back off and enjoy your rig. Someday she may ask to come with you