grid pathing system

hey guys! i got a bit of a weird one. i have created a grid and i managed to create a code that allows the user to choose a start and an end inside the grid. i made a simple vehicle that normally is only able to follow a specified target. what i need now is for that vehicle to find its target ( the start and end). then it needs to follow that path then turn around and stop right back where it started at start.

originally my idea was to just switch the game object target with the code for starting and end when i realized i didn't know how to do that...the code is way too long to throw in unity answers.

am i on the right track or is their a better way?

really? did i do a bad job explaining or something?