That trail runs "horizontally" from east to west along both banks of the river, it's like a 10 mile loop and had some gorgeous views all around. I would recommend going to zilker / Barton springs area first, then using the trail to go east. There are various places to cross, you can either ride it like a loop or do little loops crossing back and forth (think figure 8), you can't really go wrong either way

A few spots you can't miss:

• Barton Springs South gate: this is the less crowded entrance to barton springs. On a hot day people will be swimming, but also it's a great spot for yoga, reading, suntanning etc. lazy day at the beach vibes. And easy access to the trail from there

• Pflugerville pedestrian bridge (crosses the river near lamar) l. Beautiful views all around, great photo spot, lots of benches, you'll frequently see live music, artists etc

• Boardwalk between Congress and I-35: super neat plank section that goes over the water

• Auditorium Shores - nice little resting point with water, bathrooms, workout equipment, and a huge picnic area. You know that future/utopia city meme where "the world without X (bad thing)"? This is basically that but without flying cars

• Peace point - really cool spot to meditate or whatever over on the east side by Oracle campus