Drive around Seattle until you find an underpass marked "Clearance 10'6"". Drive under it at about 40 MPH. If you don't have an RV Convertible on the other side, you're good to go.
OR
Buy a couple of 12' long 2x4s and a 2x2 longer than your RV is wide and nail it to the 2x4s at 10'6". Then you and a friend stand it up and move it along the whole length of the RV.
In my case, I already had a building with 12'x12' doors where I stored my 'B'. When I swapped for my current 'C' with a satellite dome on top, I had a buddy get up on a ladder with orders to yell "STOP" if needed. It cleared with room to spare. Your RV may have the clearances in the manual, but I'd measure anyway. The manual may have an expensive rounding error.