Be careful when stepping on the rear beam: because of the shape of the hulls, your weight plus the mast will make the boat "seat back" on the rear segment of the hulls and put you in a very scary situation... This is the reason why I havn´t been able to raise the mast solo myself (any advice for this?)
Either leave the boat tied down to the trailer while stepping the mast or move your rear cradles on the trailer so they are just under, or behind, the rear beam of the boat. If you are talking about the trailer tongue raising into the air, leave it connected to the tow vehicle while stepping.