1 base. The triangular pyramid has 1 base, and that is the square at the bottom. Hope this helps.
4 tables. 4*4 is 16, meaning that even if 4 players want to sit together it doesn't make a difference. With 16 players and 4 at a table we are going to need 4 tables.
To answer this i need a little more info but it's probably going to be 30 miles.