First, see my post here: For those who "Tether"
Second, Verizon does NOT have a "hard cap". The Terms of Service simply say that if you exceed 5 GB per month, they have the right to restrict your service - i.e. make your connection slower.
I use my phone tethered to my laptop all day every day and have never had an issue. I doubt using it 4 times per month is going to cause you problems.