when we were first sailing in the US we invited many people for sailing with us.

I used a word processor to do up a tri-fold paper that acted as an invite and instructions. We added in things in a fun way that informed the guests what to (and not to) bring. Things like shoes and all. It wound up with a small map on the back. It worked out very well.

We also made up a short 1 page document to give to each guest after the day that was sort of a certificate. It stated that they acted as a crew member on the date with a short description of the cruise.

Worked out well and Cruising World published them. MANY years ago!...

Greg