I agree with just about everything you said, except the "in nature" part. Don't get me wrong, tripping in nature is awesome, maybe the best place to trip. But it isn't necessary and might not even be the best for your first time (depending on what you are doing). They real key is to not have too many stimuli out of your control, particularly having lots and lots of strangers around. Especially if you have to interact with them for whatever reason.
Other than that you are fine. As long as you are in full control of what you are doing and you don't feel pressured by strangers then most people will be perfectly comfortable. And while tripping in nature has generally been more enjoyable for me, interacting with really good friends (especially ones also tripping with me, one of the best parts of the trip) and seeing your familiar surroundings with a new mind was the most valuable part to me.