Looking to put a no slip coating on the parts of my trailer that you step on to enter the boat. I would like to go with a paint on type. I am considering the following

Truck bed coating

Rubberized no slip coating that cabelas / basspro sells

No slip additive that you can mix with paint ie Rustolem

Anybody used any of these products on trailers before? Which way should I go?

I keep a roll of adhesive backed material used on machinery and industrial equipment for that purpose.  Looks about like a black 50 grit sand paper and it's weather proof.   Just cut it to size, peel the backing off and stick it on, will be there a long time.

I agree with Way2slow. I used that on my older trailer and it is great for traction. It's not that expensive and can be cut to fit most anywhere.

Google "traction tape" and you will find a number of sources for it in different widths.