When I met my kids SOs (the first time I met them was when they stayed for the weekend) I let them guide the visit. I did my own thing, they did their own thing, we spent time together etc. I really felt that the entire experience was very natural. We had some board games that we played at night, my D’s BF cooked for us (his idea), they came and went at their leisure etc.
When the weekends ended I was happy that they were happy.