I've done customer visits before. I never planned one with other team members. I was amazed at the insights gained by having an engineering manager and a product marketing person. We used the visit request template and the visit report from the PMDR, and we've scheduled a group meeting to present our findings. We actually came up with a new product idea. But it wasn't me (the product manager), it was all of us working together. if you can arrange a customer visit and go with several people, you will be surprised at what you will all learn.