I’ve used many different types of trailer tongue locks on various trailers over the years and was shocked at how easily defeated every single one of them are after recently watching some videos showing their weaknesses. I feel that most of the options can actually be relatively effective ”keeping the honest people honest” as long as in a location where making noise will be problematic for the thief. Armed with a grinder and sledgehammer, the locks are quickly and easily defeated while making a racket. If your neighbors at the lake are not there year around, I would be more concerned. I always try to position the trailer in a place not visible from the road, as the wrong people driving by making note of a trailer not moving for weeks or months at a time have time to formulate a plan to get it out of there quickly.
I try to make it difficult by putting a lock on the hitch, a chain around the frame to a tree or fixed object, and remove tires on the sunny side. If they want it, they will get it, but it will be a little more work. Sad that we have to do this to protect stuff.
Our trailer is in a secure 24 hour monitored facility, but I use a coupler lock from Proven Industries www.provenlocks.com, which slows them down a lot more than the typical ones you get on Amazon. It's pricey but worth it to me. They're the guys who exposed on Youtube many of the cheap coupler locks as defeat-able in 30 seconds or less. We also have a wheel boot lock. It's still a simple matter for them to hook up chains under the coupler and drag the trailer somewhere else to defeat it. Simply removing 2 bolts can free up the entire coupler if they choose, and they just bolt another on without a lock.
Bottom line is if they want it they'll get it, so a tiny stick on battery powered Spot Trace satellite tracker is an inexpensive way ($50 with rebate and $50 annual subscription) to know if it is moved and where it is going. If motion is detected, it gives lat/lon location notifications every 5 minutes on a phone app or browser and works really well https://www.findmespot.com/en-us/products-services/spot-trace. It can be hidden on the trailer or the boat. The battery lasts several months depending on the settings and activity.