Driving on the lateral with a MH (in PV)- What is the rule?

In PV, going southbound you have to go onto the lateral just before the airport. You actually need to take the exit for the airport. There is a sign but it is hard to see. Do nto go onto the overpass, you will get nailed at the south end of it. Northbound you need to stay in the lateral well nroorth of the airport until the curve before the Home Depot. There is also a bridge just south of Bucerias you cannot cross, you have to go down alongside it.