Ev charging in camps expectation of availability, cost

I don't see an issue at this time. I doubt that there is one in a thousand that tow EV,s.
In the future when EV's become main stream infra structure will grow to accommodate need.
In the mean time, just tell the customer, "Sorry but we do not have the demand for EV charging to make it feasible."
Now if you want to go to the expense to upgrade for EV,s, make sure that your capability is upfront and center in all your marketing brochures and advertising.