All of the carriers use other carriers towers as well as towers owned by third parties. Every carrier has areas of poor /weak coverage in areas you would not expect as well as areas you might expect. Height position on towers, type of equipment, power, back haul from tower to an internet backbone all play into the equation. I have been in the industry for over 30 years and even though I only deal in billing, small carriers at that, I have learned a lot of things.
There are still several rural carriers out there that have to partner up with a major so they can offer their customers "a Roaming" experience that looks like you are always "Home". The big guys are the same way. Everyone of the big guys look at one thing, profitability. If the area is not profitable it will be the last to be addressed if they ever do it. The smaller local carriers, they actually care way more about their customers. You'll normally get better service and better customer service. You might not get the latest wham bam "iPhone 42 or Galaxy 75S" but you get a personal touch from folks that are part of your community.
Also on the trail cams, make sure that the cam can be added to your cell plan. I have seen some that you can't add the camera to your plan, you have to use the manufacturers plan which is often more costly and often is used to offset the costs of the cam and allow for greater profit margins.