You can buy an adapter to place on the end of you power cord to plug into either the 30 or 50 amp.It does not change the power at all. It's an adapter you plug into the 50 amp box and then you plug you power cord into the adapter.
will use only the amps it needs and is allowed by your 110v breaker.
It's all 110 volts.
Big motor homes and travel trailers require more amps to run more lights
and bigger appliances so the campground has different amperage services to supply the different requirements because the power cord plugs are different for each amperage requirement.
You will be perfectly safe.