It is illegal to consume marijuana openly or publicly, or anywhere that is accessible to the public. Consumption is exclusive to the patients property or on personal property with permission from the landlord. Be sure to check out local laws if you will be traveling throughout the state, as some municipal counties can have stringent laws as well.
The right to possess or consume marijuana and marijuana-infused products does not apply to federal lands within the state of Colorado, including national parks, national forests, national monuments, and any other federal property such as courthouses. Please be aware that many ski areas are located on federal land.
The answer is no. Marijuana is still illegal at the federal level, and since the United States Postal Service is a federal entity, anything involving marijuana is prohibited via the standard snail mail route. Shipping/mailing marijuana is considered to be trafficking according to the federal government, and is strictly prohibited, so any type of activity with any entity (UPS, etc.) is against the law.