Hi Andrew…Assuming you are the one who asked for the Tutorial in my YouTube channel here is how i did it.
First in my Vehicle Blueprint i added a box trigger. Then in box trigger overlap i checked if the overlapping actor is my character and if it is then execute an Event in my character. See the graph: http://i.imgur.com/iiJ492H.png
Then in my character Blueprint i simply possess the vehicle and run a vehicle specific Interface function (optional). See the graph: http://i.imgur.com/A26B9Pu.png
The Vehicle Possess function you see in My Character Blueprint is this: http://i.imgur.com/iZe2Myc.png
NOTE: These graphs were created in Unreal Engine 4 Beta build which didnt had Blueprint communication. Now that Blueprint communication is available you can use that feature instead of Interface.
Hope this helps.