To tarp or not to tarp, that is the question...

I'd suggest to get all the possible leak points sealed up good, first. An hour or two with a caulk gun loaded with Proflex RV should be all that's necessary. You could certainly use the canopy as long as it's stabilized and doesn't fall on the trailer.

Here's my rig under going a leak test:


That is 8" of very wet heavy snow--Minnesota Mortar. I don't cover the trailer at all.