Have people around the lake called Verizon to complain and ask to file a formal report of the problem? If they get several reports they should look into it, especially if reported that it has changed from ok to poor service.
As an alternative, you can get a "network extender" (I have one at home), but most phones now support the wifi calling feature, which must be first enabled on your phone under "advanced calling" to be usable. Either can help.
https://www.verizonwireless.com/supp...-calling-faqs/
Here is the information on the network extender (techies call this a femtocell, cellspot or microcell device) which seems to be limited for use only with 4G phones:
https://www.verizonwireless.com/prod...sku=sku2490003