Lucia, I completely agree that the easiest way to take hallucinogens is in the daytime with abundant sunshine and natural beauty present, however, I have found that mushrooms seem to be more rough than acid on a consistent basis.
For me, mushrooms is tough love. Mushrooms test you to see if your actions match your words/beliefs and frankly, they can be a bit rude in communicating their message. You are forced to evaluate yourself in a sometimes uncomfortable and serious setting (intense introspection). Everything that you push to your subconscious so that you don't have to deal with it, it gets dug up here and you have to face it before you can let it go (facing your demons, nearly literally). There is immense potential for personal growth, but mushrooms tend to be eerie and difficult for new users at times.
Acid is different for me. Usually you spend the first stage of acid being insane on some level (higher levels of psychosis can happen in higher doses), but at lower doses it's not bad at all. After some time tripping, it seems like all your habits have been temporarily erased. For example, when you get into the car, you put the keys in the ignition, you put your seat-belt on, and perhaps you switch to your favorite station. When on acid, you get into the car, you find yourself sitting there, not performing any of those activities like you do as second-nature during baseline states of mind. This is an excellent tool as it forces you to hold onto intention to operate and it forces you to observe things that have always been there, but you are so stuck in habit that you never once noticed them. By simply observing and pondering, you seem to find some incredible insights. You learn that in your day to day, you're actually not as in control of your body as you thought (habit actually lives your life more than you'd believe). By holding onto intention and being aware of your actions, you gain control of your life.
Anyways, this was meant to be a more casual comparison to support my advice, but as I was saying, I think maybe 1 hit of LSD is a good introduction. Sorry for the prolonged post!