Recommendation boosting cell service while traveling

[WYNLIN7]

I saw network extenders as a topic but I don't think this is the same.

Despite being told by workmates and company that Verizon has the best coverage, its not completely true. It is at airports, major cities, etc. 

But going home to visit my folks in Central Illinois (Morgan County) my signal is so poor - I often can't use my phone for calls. Wi-fi helps considerably but if I'm driving around...

Knowing this problem is real - has me wondering. I plan to buy a travel trailer and do a lot of sightseeing and spending more time with mom and dad in their golden years. Ive been seeing mobile phone booster devices.

Assuming all things equal (works with my phone and tablet) requires a place for antenna, electrical, etc...What is a good solution to stay in touch? I can't always count on WiFi even at public campgrounds. I saw a post from a year ago and I believe they might be using one such device but they had problems accessing because of lack of postal address/911. I think a non-verizon employee answered and said to just give a valid address even it its the next town over. Does that work? 

Like to hear recommendations from users and any "gotchas".

Wynne