I doubt you over stepped SketchUp's abilities but possible those of your computer. It might be that you are running a bit before you've really learned to walk. There are good strategies to deal with the sort of stuff you are doing and ways to make it less work than it probably is for you right now. Good housekeeping methods are a prime thing here. You mentioned that you are planning to do some renders. While you are cleaning up your models, make sure you don't have any exposed back faces. Some rendering applications won't render them even if they have materials applied to them. If that's the situation in your model, you might find it very frustrating so cleaning up your models in advance will help reduce that, too. It sounds like you are looking at this as a learning experience so that's a good thing. Keep plugging.