How can you not go????
I find myself in or near Milwaukee a few times a year and I always go to the museum. The staff in the museum are all great. If you have time, take one of the tours so that you van see the collection of bikes that are not on display. I believe you have to book that tour in advance. If you are a HOG member, you get free admission and a pin. After you hit the museum you have to stop by the HD store. They have items there that you can not get anywhere else.