The tunnel is over 13ft as I recall from our visit last week. There is also a parking lot prior to entering the gate where some folks staged their RVs and just took their tow vehicles. Not sure if that is an option for you or not. You can call the visitor center as well to see what your options are. +19705294465
Not sure what the height is you can call the visitor center they don't allow tower in trailers past a certain point but it's a great experience
They might ask you to leave it at one of the campsites. As far as the tunnel clearance I remember it being either 11 or 12', but don't hold me to that.
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