I have used 1 1/2" boards (like moallen explains) for the last 45 years and always have worked for me. Most of the time you only have to use one board. Mine are 2 x 6 and the board I use the most has 4 x 4 stopper. Never have used the plastic except for wheel chocks and they will be gone to (the appearance is totally gone). Carry about 10 4 x 4's x 12" with a 45 taper for wheel chocks and level blocks. And still bring along less than 1000 lbs. Wood is cheap and last a long time and for emergency you can stay warm.
2014 Ram 1500 CrewCab 4x4 5.7 Hemi 3.92 Rear and Air Lift 1000
2005 Jayco Jay Feather LGT - 29Y GVWR-6500 lbs.
Pro Series 1200 lbs. WDH with Double Sway Bar.
Champion 3100/2800 watt Inverter/Generator-Onboard Solar Power
ALJO 'Forever Young @ Heart' provide on their travels Music Entertainment to Senior Care Homes