You can do the egg crate, that is the preferred method of most here. I have done LECA for both of my builds and have no issues with it. I think the egg crate would work much better for a water feature if that's what you're planning. The LECA is sufficient just to create a drainage layer for your plants. Your plants and dirt will need some type of drainage. No matter what, you're going to need to do some type of layering. You could always section off a corner or two of the tank to build your planted sections instead of doing the entire tank. That way your handicap frog will not be pulling himself through dirt but you'll give your tank the benefit of live plants.