First, typical water pressure in S&B is usually between 80-100 psi while in a TT between 40-60 psi. The TT has flexible plastic pipes so it can't that high pressure supplied in many campgrounds therefore an add-on external pressure regulator is highly recommended.
Second, there are two types of pressure regulators - adjustable and non-adjustable. Non-adjustable ones are the cheapest and most commonly used. They output pressure typically at 40-50 psi. The adjustable ones will output at any pressure up to the supply line pressure. At 40-50 psi, both regulators will output very similar amounts of water. So if you want more water volume go with an adjustable regulator set to a higher pressure.
Third, be sure to attach your regulator directly to the campground supply spigot and then attach your water hose to the regulator. If you attach the water hose first, you may get a water leak at both ends of the hose.