Wood Swing Set For Sale Building A Wooden Swing Set.Pros'/Con's Of-Carriage Bolts Vs. Nails..Pressure Treated Vs. Kiln Dry Wood.HELP..

Building a wooden swing set.Pros'/Con's of-Carriage bolts vs. Nails..Pressure Treated vs. Kiln Dry wood.HELP.. - wood swing set for sale

I build a wooden play structure / swing. It is more than 5 square meters, "the slide, ladder, rock wall and canopy. (Madera) normal rate. You also have the 4x6 beams to the team that changes is supported by 2-3, etc. .. Supported by a narrow FIG.
MY QUESTIONS ....
I use products like 4x4, 2x8 is smaller (Sandbox) 2x4/2x6 rest ..
Carriage bolts CALLS TO 60 5 / 16 "x5" (electrically) ... Co-Wrker said that I can use 16 d nails (galvanized)?
ALL PRO / CONS ??........... On the nails vs screws' s
ALL PRO / CON pressure treated kiln dried lumber ...
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I will use the structure PTfor / Fort = 4x4x8, 4x6x10 and swing width = A-frame, and finally ... .. But the rest?
BALTIMORE AREA IS .. Hot / humid summers of the cold snow?-Winter ... dpt with H.. for the supply of wood?

ANY HELP / ADVICE / LEADS would be nice!
Thanks .. .. GO O