Note that VisualRF has no logic to model outdoor antennas in free space, as the rf propagation model is built around indoor models. The best option is to use the 3D Outdoor Planner and Google Earth to model different antennas in the outdoor areas you are looking to provide coverage for. Note as well as part of that modeling that you need to account for the additional loss of the connectors/jumpers to go from an indoor AP to an outdoor AP (additional connectors/jumpers, additional LMR, etc).
https://outdoorplanner.arubanetworks.com/
If you don't have an account, you can register and then read through the 3DOP user guide. If you plan on using an RP-SMA connectorized antenna, just find the outdoor equivalent to model with inside the planner.