Looks like you're leaning toward a day hike. That is what many hikers do--you just need to be in good condition. Running those half-marathons helps.
The other is acclimatization. If you live at SLC, then you're already at 4k,so that gives you an advantage. Most hikers in CA live near sea level, so they are way more affected. I was going to recommend spending a night (maybe in your car) at Horseshoe meadows, but then I looked up the SLC elevation. That is likely why altitude has never been a problem.
For a day hike, start early, but not so early that you don't get enough sleep before the hike.
