Re: one week driving trip from Tahoe to Grand Cany
Consider something like this:
Sunday: Start Early down scenic highway 395. Visit Yosemite Valley and stay in Lee Vining. Yosemite really takes an entire day so you may not get to see it in the detail you would like without staying closer the night before, or staying in the valley that night (expensive). It will also be very crowded with tourists on a Sunday so getting around will take longer.
Link to map
Monday: Mono Lake, then drive to Mammoth Lakes for breakfast / lunch and possible sight seeing (Twin Lakes driving loop?). South to Bristlecone Forest, then to Lone Pine.
Link to map
Tuesday: Watch the sun rise on the Sierras and Mount Whitney. Drive to Death Valley. There are many places to see here including sand dunes, Zabrisky Point, Badwater, Race Track, Artist's Drive, Scotty's Castle, Devil's Golf Course and more. To see everything will take an entire day. It will also be very hot! Stay the night in Furnace Creek.
Link to map
Wednesday: Drive east past Las Vegas to Hoover Dam. Tour the dam and return to Las Vegas for the night. Honestly I don't know what the best route is from Death Valley to Las Vegas. It's all hot, boring, barren desert. I've taken 178 over Salisbury Pass and it's fairly scenic, but going out 190 to 95 (as suggested by Google Maps) might be faster. Ash Meadows Road through Pahrump looks shorter and very interesting but I've never taken it. Vegas is best seen on a weekend night for the full effect, but arriving late evening to early night will still give you all the lights without the crowds. There is a lot of night life and plenty of shows if you want a night on the town.
Link to map
Thursday: Drive to Grand Canyon South Rim. Keep in mind that distances don't look very far on the map, because there aren't a lot of roads in the desert. But there is a lot of driving involved on this trip!
Link to map
Alternate: If you want to shorten your time in Death Valley, you could continue to Las Vegas on Tuesday Night. Wednesday morning see Hoover Dam, then head north to Zion National Park in Utah. Stay somewhere in the area and drive to Grand Canyon on Thursday. You may even have time to visit the north rim of the Grand Canyon on the way.
My only real concern is the very long first day. I hate for you to be rushed in Yosemite but I don't see any other way to do it unless you cut out another sight and shorten all the days a bit. You could then stay somewhere near the west end of Yosemite and drive back through the next morning. Anyway, I hope this gives you a good start!