HogGirl - I was feeling similar to you last year when my 88 year old MIL also said that she wanted to attend the four days of commencement events at my DS's school on the other opposite coast from where we lived. Logistics and not having a pre-occupied mind were my concerns. As others have said, anything can happen in 18 months and your ILs may change their minds. Like your friend suggested to you, my husband and I took my MIL to visit our DS who was performing in a concert on a weekend in March. We gave her the grand tour, showed her where the places where the graduation events would be taking place, bought souvenirs, met some of his classmates, and ate out at favorite eats. It was a relaxing and wonderful time as a family. After that, she was happy to stay home during the graduation and watch it live stream with a campus map and booklet in hand. We also Skyped her during the festivities so that she felt like she was there (minus the humidity, crowds, walking, and busy schedule). Hopefully, your ILs will eventually consider this option.