I am planning to install a kit gazebo in the back yard. I plan to install a 15 or 20 amp GFCI breaker in the panel and run 14/2 or 12/2 (as appropriate) UF cable to the gazebo buried at a minimum depth of 12". I will put the cable in conduit on the exterior of the house to 12" below grade, and the cable will enter the gazebo through a 90 degree sweep placed prior to pouring the concrete slab into the hollow wooden gazebo leg. I am reasonably confident that this will meet NEC (and local) requirements for running cable from the house to the gazebo.
I plan to install an outdoor rated ceiling fan under the gazebo roof, and a lightswitch and an outlet mounted in weatherproof boxes to the gazebo legs facing the inside of the gazebo. Getting power from one of these locations to the others will require me to run cable through the hollow gazebo legs and along the roof rafters. This is where I'm unclear about requirements.
If I run the cable through the hollow leg of the gazebo to the roof rafters, and secure the cable to the top side of the rafters appropriately, would I require conduit? If not, how frequently must the cable be secured to the rafters and what fasteners are appropriate?
I believe this would be a NEC 'damp' location. Can the same UF cable used for the underground run also be used inside the gazebo legs and along the roof rafters? If not, what cable should I use?