With just 2 days, and wanting to get in a couple of hikes you'll need to keep busy. I don't know at what time of year they'll start the bus to Glacier Point, but if the road opens soon and the bus trips begin by the 15th, you might consider taking an early bus from Yosemite Lodge to Glacier Point, and then walking down the 4-mile trail to the valley. This gives you a nice hike with some great views, you get to see the Glacier Point view, and the bus ride in itself is informative. It's a relatively easy hike since it's all downhill.
I see fresh snow today at Glacier Point (via the Sentinel Dome webcam) so this may not work...the top half of the 4-mile trail could be closed if it's snowy or icy. The website may tell you if the trail is fully open, or you can check at the visitor center when you get to the valley.
For your 'waterfall' hike, you could still use the Mist trail as suggested; once you get to Vernal Falls, you may decide "that's enough!" after the steep steps and very wet conditioins, but the nice part is you can opt to continue to Nevada Falls or to go back after Vernal.
Or, the Upper Yosemite Fall trail is fantastic, but I'd rate it as a VERY strenuous trail (I'm a Half-Dome hiker, but the upper falls trail is a tough one, no two ways about it...up, and up, and up). You can go part way though, past the great views of Columbia Point (about a mile up), a bit farther to the base of Upper Yosemite Falls. Most people don't make it much farther than that, and while it's a pretty hike from there, you soon lose the falls view until you get to the top. If there's any fresh snow on top, you won't be able to find the trail to the falls overlook anyway. If you go all the way and back, I guarantee you'll be exhausted, so keep that in mind since your visit is short.
Of those two falls hike choices, I don't know which I'd pick, they're both great; Vernal-Nevada will be more crowded but is easier, despite the granite steps.
If you can't or don't do the 4-mile trail part, you mentioned Inspiration Point; there are different ways to get there, but you might try the Old Wawona Road, which will take you past artist point and at 2.6 miles, to Inspiration Point (actually on the Pohono Trail). You can find the Old Wawona Road by walking up highway 41 from the Bridalveil parking lot, about 1/3 mile...it's the blocked off road, and a pleasant hike. Or, you can take get on the Pohono trail near Tunnel View, if the old Wawona Road doesn't interest you.
Anyway, enjoy your visit; I just thought I'd throw in a couple of ideas to confuse things, but you can't go wrong in Yosemite unless you leave early 8^)
Gary
Yosemite Photo Galleries: http://www.pbase.com/roberthouse/yo