Trailer hitch strength questions

I'm finally starting my trailer project. Getting the bike prepared first. It is an '83 1100 without linked brakes. The bike does have Interstate bag mounts and crash bars
My question is about attaching a trailer hitch. I see Markland hitches advertised and wonder if the bag mounts on an Interstate are strong enough to pull the trailer or do I need to add more support tied into the passenger footrest mounts? Pics available if needed.

My other question is what the recommended trailer wiring equipment is. Some folks talk about a 4 or 5 wire converter. What's popular? I would like brake and turn to function at the same time with multiple filaments (bulbs)

I have a Markland and seems plenty strong with no other added supports.

4 wire plug is
Ground
Left
Right
Running

You'll need a wired in convertor that converts the separate left/right turn on the bike to a combined output for the brake lights.

I have a U-haul part number 14493 harness on my 1100, which is everything Dan mentioned. As far as the trailer hitch goes, I also have the Markland and don't see any need to add anything as far as support goes. Keep in mind, you'll be pulling hundreds of pounds... not thousands.

I ran a 6 wire plug and used 5 wires. The 5th wire I used was so I could charge my tablet, phone, camera, batteries while riding.