I really like riding by myself sometimes, especially days midweek when the resort isnt busy. I put my headphones in and sing on the chair lifts. When I am by myself and it is busier I talk to people on the lifts up.
I have never been on a longer trip by myself but I would go to the bar and have a drink or two and socialize with whoever was around. If you ride all day you will be ready for bed early.