I do the same thing. I pick where I want to start and see what real life flights are there and pick one I want to do as long as the matching aircraft and livery are in IF. Then I pull up the real life terminal map and pick an appropriate stand to start from. I make my flight plans in simbrief, copy it into IF, set my weights and fuel as stated in the plan, get the charts out (especially the taxi diagrams) and off I go.
One, I simply prefer to be prepared, and two, it gives controllers a clear picture of what I’m thinking. Obviously, aside from cruise, you’ll usually never fly the plan exactly. Even if I’m going into an uncontrolled airport with zero traffic I’ll usually shortcut the approach if it’s safe to do so and visibility is great.