You need to be careful in removing antennas on the roof that the roof remains weather sealed. You don't want water entering the attic where the lag screws used to be. Additionally, I've seen installations of antennas on the roof where removing the dish antenna also damaged shingles under the mount. If you don't feel comfortable removing the antenna call a local company that installs for Dish or DirectTV and pay them to remove the equipment.

sorry for the late reply, hope this helps.

if the dish is mounted thru the roof, you can leave the base plate and just remove the dish and mast. if you do unbolt the base, simply fill each hole with SILICONE or ROOF PATCH. do not use CAULK.

if the dish is mounted to teh side of the home, caulk is fine to fill the holes.

as far as the international box, just remove it. the cables for it and the dish should just be coiled up and tucked away under the eave. you never know, you may decide to put an antenna up to pick up the new DTV channels over the air soon and these cables could come in handy! if you are 100% sure you will never need them, then cut them off.

i have never dealt with teh international box, but the dish itself has no voltage going to it when there are no receivers hooked up. even then it is car battery voltage, not deadly house voltage.