If you're in town early and want to take a slightly longer route to Timberline Lodge, we HIGHLY recommend driving through the Columbia River Gorge along I-84 to Hood River, then around the east side to the Lodge. This would add about 30-40 minutes to your drive, but we think it's worth it (especially on a nice day!). The Gorge has stunning waterfalls and towering cliffs, which you can enjoy from I-84 or quick pull-offs at scenic overlooks.
If you end up out on I-84 (either going or coming!), we recommend a stop at Multnomah Falls. There's parking just off the highway (though it does tend to fill up on particularly nice days). At just over 600-feet tall, it's Oregon's tallest waterfall!
Hood River is a cute town on the I-84 route along the Columbia River known for being the birthplace of windsurfing. It's a great place to grab a bite to eat (many more options than in Government Camp) or spend some time before coming up the mountain (if you take the longer route through the Gorge). This could also be an option for breakfast the morning of the wedding (again - more options to choose from!) as Hood River is a ~1 hour drive from Timberline.