Like Odonata, I’ve fished a bunch of Sierra creeks and lakes over the years. I seem to be gravitating towards 7.5ft 4wt with backbone as a decent all around rod for creeks and lakes. My goto rod has been my Scott F (black glass). I’m usually not pushing giant flies or multi-fly indicator rigs at high altitude and the Scott works well even in a breeze.
Wind is less of an issue along creeks, but it can get pretty windy on high Sierra lakes. If you really want to cast distance in high winds on lakes, I recommend you go with a 5wt or 6wt 9ft fast graphite rod - it makes it easy to get good line speed and punch thru the wind. Not that much fun for smaller fish, though. I think my current compromise rod is the 7’ 5/6wt LLBean (made by Timberline) rod I picked up last summer. It is short enough to maneuver around bushy creeks, I can push line out pretty far with it, but it’s still fun with a little fish on. For fishing around Tuolumne Meadows, a 3wt or 4wt glass rod should be just fine for both the Lyell and Dana forks. Those are fun creeks and they should have plenty of hungry fish in them.
When you consider carrying two rods vs one, everything is a trade off. If you skip the rod tube, a second rod and reel is only around 10oz or so. I usually go with pretty minimalist tackle set. Here’s a post with the rig I carry:
https://fiberglassflyrodders.com/forum/viewtopic.php?f=2&t=69798 (and pictures below). You’ll note: no vest, only one fly box, no split shot, and minimal tools. It’s pretty light. Adding a rod to this wouldn’t be a big deal. The rod tube is a plastic fluorescent tube protector you can get at your local home/hardware warehouse store.
Your other issue is what flies to take. If you hit your favorite search engine with “high Sierra fly box” or similar, you can get some pretty good lists. You don’t really need a crazy wide selection. I usually end up catching fish with attractors like Parachute Adams, black ant patterns, grasshopper imitations, and basic small nymphs like Copper Johns. Small streamers work too.