I’m not sure about digging or running lines.

I mentioned to the owner that the straightforward simplest solution is to run a secondary line to the house from their service provider. But that it’s an additional monthly cost as that provider will bill for a separate line of service, not to mention the recurring or initial cost of a modem. They weren’t wanting that and I mentioned I wouldn’t usually recommend it either because of that extra cost of almost $100 a month.

She is also 80 years old so I’m trying to find something which is as basic, and serviceable/replaceable as possible for whoever might come out to help her with it in the future, with the assumption it may be a less than technologically familiar person.

And it’s unlikely she’ll agree to drilling a hole in a wall for a cable as she’s a widow and the house was her husband’s dream home project. So, limited in options and trying to find some electrically powered device[s] to keep it simple.