The more facinated you are by the subject the better you'll study the design.
If it were me, I would vist every builder and/or view every boat I could find. bring a pad of paper, pencle, and a camera: take pictures, make notes and sketches, paying careful attention to the details of how the engine is mounted, how the riging made and secured to the striingers and so on. At first they'll all look the same and maby even confuseing, but as you study them you'll start to see the diffrences in design as well as the similarities found in most all boats.
Before you go snooping around somebodys buisness or yard, go and talk to them, tell them what you'd like to do. Chances are they'll go out of their way to help you, especially the commercial builders who might see a chance to sell you some pre-fab rigging.
I can completely understand the desire and necessity in building it yourself, however that may not be practicle: as a suggestion, there are quite a few builders that will sell you rigging and engine stands with as much or little built as you desire or can afford.
At the very least (unless you're a competent metal fabricator) I would buy a ready built engine stand, especially if you've got a Lycoming Aircraft engine.
BTW: you mentioned a prop with the engine: did it come off the airplane? If so, it's proabably a "tractor" type and won't push air out the back. The up side to this is AC props are very expensive and you could proabable sell it for enough to buy a decient new prop.