There is a Bus that goes from the SeaTac airport to Olympia. It is an easy and safe way to get right downtown Olympia only 10 min from the venue and walking distance to hotels. Pricing is roughly $5 each way. Ending location would be Olympia Transit Center. The Bus ride takes about 2.5 hours. Driving time can be anywhere from 1-2 hours depending on traffic.
Ride sharing apps (Uber, Lyft, etc.) can be limited in Olympia so we suggest that you carpool where possible. There will be ample parking at the church and at the Moreau house for the reception if you choose to drive.