Vail Village is just over 8,000 ft elevation. You may experience the effects of altitude sickness, such as headaches, tiredness, lack of appetite, and nausea. Altitude sickness may worsen with exercise and alcohol consumption. If you're not accustomed to the elevation, consider taking things a bit slower until you acclimate, and be sure to drink PLENTY of water throughout your stay.
Lionshead is slightly smaller than Vail Village, but there are still restaurants, bars, shops, etc. Walking to Vail Village from Lionshead takes about 10-15 minute walk, and there is also a free shuttle that runs every few minutes.