What's the best way to hang a tennis ball on a string to use as a way to know when to stop the truck in the garage? By that I mean while I have the truck parked in there. My **** is too heavy to not dent the hood sitting on it, and reaching over the truck from the side to get the thing in place is challenging - my balance ain't what it used to be. I need some tips here. I know there has to be an easier way to do this, I just can't figure out out. 
Btw, this wouldn't be an issue if I wasn't dealing with literally a couple inches of space in front and behind the truck when the man door is opened.

Btw, this wouldn't be an issue if I wasn't dealing with literally a couple inches of space in front and behind the truck when the man door is opened.


My method was to just eyeball the height part but the eye bolt is a good idea. I did beat you to the punch with the pencil on the broom handle though. LOL