Congrats on your new trailer! And ...... snow....
Sure has been a rainy November, hasn't it? December isn't any too dry either, so far
I'm not sure they'll have the 3M#225 at Home Depot, but Amy (who just brought home a Boler
with a few leaks) found a variation at either HD or Lowe's, I believe. It was in her "Where are their RV repair pros in Washington" thread, if I remember correctly (or similar title).
The main thing is not to get regular duct tape, nor the blue or green. That stuff will turn to concrete after a few weeks
Rivets aren't too hard to replace. But also know that the caps are semi-cosmetic. I say "semi" because all of the rivets that are typically used at the factory in our eggs have a hollow center. So of course that can leak. Bolers and trailers that don't use caps just put a small bit of caulk on the center of the rivet, covering the hole. Scamp
uses caps to "hide" the rivet, and you can also put sealant under the cap.
So if you have a rivet without the cap, the first thing to determine is whether it is loose or leaking. If it's loose, well, time to replace. If it's tight, but leaking, you can probably put a dab of caulk (not silicone!) over the center hole. Or a new cap top + caulk.
If the cap base is deteriorated, then you have to put in a new rivet, because the cap top snaps onto the base, and the base goes in along with the rivet. A deteriorating base can cause a rivet to be loose for this reason.
I don't happen to like the caps, but that's just because they look "pimply" to me. I'm sure other people would rather see caps than rivet heads
Of course temporarily, you can also put some of the all-weather tape over a leaking rivet, if you can dry the shell.
Typically, there are cap nuts on the inside of the rivets. You put these on the inside end of the rivet before you squeeze the gun to install it, and then it pulls the nut on as it "makes" the rivet. Some people use acorn nuts - they are very similar but just a hair more "cone heady" than the cap nuts.