A piece of advice for surviving family visits when autistic is; get out and do something at regular intervals. The close company of people overloads me so I make opportunities to get out.
My parents live by a river so I go outside immediately on arriving there to take photographs. I need to do this to make up gestalts for being there and having lunch. If I did not do this anxiety would overwhelm me and I would have a quiet meltdown.
I have found that people don’t mind me going out for space when they know I am autistic and I need to do this. They appreciate knowing that I like them and I am not snubbing them by doing this. When they know I need to manage my anxiety this way they are happy for me to pop out at any time. This is a huge relief to me and enables me to socialize.
Do you have children who melt down when out? One tip I have is to give them space to get away from people so they can manage contact in short defined and time limited steps. Also when they need to go they need to go. I recall on new years eve that at 9:00 pm my anxiety was so high I had to go home. This is not being awkward it’s simply a matter of managing anxiety.