The US is an extremely diverse society and attitudes towards LGBT people differ hugely across the country. LGBT travellers may be affected by legislation passed recently in the states of North Carolina and Mississippi. You can find more detail on LGBT issues in the US on the website of the Human Rights Campaign.
Laws vary from state to state. When you are physically present in a state, even temporarily, you are subject to that state’s laws. You must carry a passport showing that you have leave to enter or remain with you at all times.
Possession or trafficking of a controlled substance in the United States can carry a severe prison sentence and/or fine. Check with each state you are intending to visit to make sure you comply with the personal possession and consumption laws of controlled substances within those states. A list of all types of controlled substances, as listed under the Controlled Substances Act, can be found on the US Department of Justice website.
Take out comprehensive international private medical insurance and travel-health insurance before you travel to the USA.