Teardrops n Tiny Travel Trailers

I unfortunately have a few gaps where the exterior wall meets the plywood which will support the aluminum skin. I have read a lot posts regarding sealants and caulking and have found myself confused as to the best choice for this situation. I would be grateful for some recommendations as to the best way to seal these gaps. Thank you for taking the time to share your recommendations.

If it's "bare wood" on bare wood, I've found PL Premium to work well for situations like what you're describing. PL has good gap filling ability meaning it does slightly expand upon curing/drying. If you're able to pull closed your unwanted seam with a pipe clamp, all the better.

A door and window caulking like one of the ISO Quad sealants is good for gaps like this. It's sticky and has the elastic qualities you need for something like this, it's designed to deal with larger gaps and movement. It's typically what I use at work when hanging doors and setting windows unless I'm on a big job, then it's Dow which typically has to be bought by the case and is often spec'd by the architect or building envelope specialist. You can get ISO at the big box. Another option would be Dow 195, not as readably available to consumers.