For the limited amount of play it is going to get, I wouldn't mylar the playfield. Just be sure the balls are new, (i.e. completely smooth) and that the shooter has a good bumper on the end so the ball doesn't get damaged. Playing with a damaged ball is like slowly sanding the playfield.
I would touch up any paint damage on the playfield if there is any, then keep it waxed well.
If you mylar it, eventually the mylar will wear, and then what do you do?
Just my 2 cents worth, and what do I know..... ;-) I need to be sure you take good care of it so in case you ever decide to sell it, I can buy it and move it next to PINBOT!