I have a similar issue in my garage where I need to be in a certain spot side to side in order to open my slides without them hitting the wall, and space is tight so I wanted it to be close but not too close. My solution was painted stripes on the floor right where my wheels need to be. If the wheels are on the stripe I'm too close but if they are off it I am just right. Sometimes I have to pull out and in a couple times to get it right. A bit harder for you with a 5th wheel but doable. They also sell yellow/black floor marking tape at Ace.
I have Tire Skates but even moving a car around in the garage can be a challenge and if your driveway is sloped at all you could have it roll away on you, plus there's the hassle of putting them under the wheels.
Now if you want easy but not cheap there's always these if your weight will fit:
https://www.zendextool.com/product-c...k-wheel-dolly/