DON'T back your vehicle's tires into the water when launching or retrieving your boat!!! Be sure to apply parking brake and make sure it is holding your vehicle in place on the ramp BEFORE you even open the door!!! I won't go into manual transmission procedures as hopefully you know them if you can drive one :-O
Your trailer's winch is capable of pulling your boat into position if you aren't comfortable powering it fully into position.
Also..and this is a biggie. DO NOT EVER LAUNCH YOUR BOAT KNOWING IT HAS FUNCTIONAL ISSUES for a quick time out on the water. Boats aren't like cars in that most of the time you can't just pull over and flag someone down or call a friend to come pick you up. Unless in shallow enough water and equipped with proper anchoring gear boats generally don't just sit stationary when not under power. Sometimes this may not be an issue, at others they could wind up having the tide/current/wind take them offshore, toward a dam, or just farther from shore in bad weather.
I grew up commercial fishing in every setting from rivers, marsh, to the Gulf of Mex. on everything from pirogues to shrimp trawlers and worked the oilfield on crewboats and supply boats. I took it for granted that everyone piloting boats knew about them. They might be jerks in 50' sport fishers with no sea manners but I figured they atleast knew about handling their boats.
Moving to S Fla (Miami, Key Largo, and Ft Myers) and being around freshly retired snow-birds, week-end warriors, and vacation rentals shocked me. Its the things you will take for granted as an experienced boater that you won't think to tell a new boater that will get them into trouble first. Stuff like boats don't have "brakes" and just because you can see water doesn't mean its deep enough for your boat to navigate there, etc.
I agree that your idea is noble, but time and hands-on instruction with instant question/feedback are what is needed for someone totally green to boating. Would you feel comfortable knowing a significant portion of the cars coming toward you on a two lane undivided highway had watched a couple of videos and were out "giving it a shot" on the road with you?
TIME well wasted
1984 34' Mainship III