Canvas or vinyl...

I like the smell of new canvas (or old canvas for that matter). Canvas would be in keeping with the vintage of the trailer. However, it is not waterproof. You would need a ridgepole of sorts to keep it elevated and off your load. If the canvas touches anything while wet, it will transfer the dampness.

With the old military style tarps, the rope can be woven from grommet to grommet so that it forms loops to pull down over the hooks. One pull on the loose end and a knot will cinch it down tight.

 

Update...

Bought a canvass tarp at TSC for $20. Will buy the pvc this week for the bow set-up like Mike did. This should work well.
I'll keep you posted.

 

Man, you're quick! I bought my PVC today from 'Da Depot; but 'prolly won't get to it until later this week. Pics, pics, pics...R)

 

I put together one of the PVC tarp supports that Boyink described last year. Mine does a fairly good job shedding water except at the ends especially if the tarp ropes are not fastened tight enough. The only complaints I have about the setup are the looks and the PVC warping that takes place when the sun is concentrated on one side of the trailer. It then looks like a lopsided Calistoga wagon. I would prefer to see something a little lower profile with supports made out of metal or wood for whatever it's worth.

 

Dang, Sparky,

That looks very nice - almost like it was Custom Made for it!