I did the same for my driveway (but from scrap wood) BUT for traveling the
light weight plastic ones seem a better choice when on the road.

>I made a set of levelers using a pressure treated 8 foot 2x6.  I cut the
> 2x6 in half and then each half again into 3 pieces with one 24" one 16"
> and one 8" with one end of each cut at a 45 deg .  I stacked the 3 pieces
> with the straight cut all at one end and screwed them together.  If I have
> a campsite on which I need to level, I place one of those bubble levels
> with 2 right angle levels on the sink cabinet and place one or both wood
> levelers under the wheel(s) that need to raise up and just drive up to the
> step needed to level the van.  The two levelers nest together and I
> usually store them behind the passenger seat.  I have also put them up
> above in the storage area with bungee cords.
>
> Evans Waldron
> 83.5 Westy Dabus
>