I am looking for a dog trailer too. I had a kid trailer that I tried to convert but, I really want one that folds down so, I sold it on CL. REI has some I have been checking out. Love that Burley and have heard great things about them

Treats and food has always worked for me when I introduce the pooches to a new thing. Also lavish with praise at how awesome they are for being in the trailer. Our Shih-tzu LOVES trailer rides