I am a big fan of this forum. With much pleasure and great interest and read all the tips everybody is giving eachother. Good tips! So that's why I would like to ask the following.

Coming May my friend and me (from the Netherlands) will be going to America for a month. NY, San Fran, Napa and of course the loop from Yosemite to LA. We know where we want to go (Yosemite, Death Valley, Las Vegas, Bryce, Zion, Grand Canyon and everything in between) but we are a bit worried about accomodation and... worried that there is not a lot to do between Death Valley and Las Vegas. We have a reservation at the Luxor in Las Vegas on May 15 but are already in Death Valley on the 12th. What to do between DV and LV in three days? Luxery problem, I know, but maybe somebody has a tip? Thanks a lot!

Death Valley will likely be very hot by then, limiting outdoor activity (hiking, etc.). Are you able to change your reservation at Death Valley to May 13 or 14? Death Valley is great to explore, but not in May, usually. It is only about 2 to 2 1/2 hour drive to Las Vegas from DV.
You will enjoy having more time in other California areas before getting to the amazing Southwest!

Yes... it is hot I know (second time a long time ago but remembered the heat ;-) and would rather not spend too much time there. Changing it to the 13th of 14th is an option but then we have to spend a lot of time in Yosemite. Do you have a tip for another route?

You may or may not know this, but the most direct route from Yosemite to Death Valley, which is Hwy 120 over Tioga Pass closes in the winter time and doesn't generally open until late May or sometime in June. The elevation is very high, so once the snow closes the road, they don't plow until spring time.

So this means, your route to Death Valley will take you south through the California central valley and then east further south.

how many days did you want to stay in DV? I adore DV and we were there in the dead of summer. It was hot hot hot but to me, it added to the unique scenery. Coming in May will be quite nice compared to the dead of summer - on top of that, hopefully you will catch the beautiful spring flowers. I remember them being around May/June.
The drives are loooong from one place to the other but well worth it. The racetrack is incredible to see and you can also go up to spots like Aguerberry point (in the higher elevation) to catch the "cool breeze". DV has the lowest point at badwater but did you know that the highest point in the continental US is Mt Whitney at the sierras which is about a distance of 135-146 miles. They have the badwater ultramarathons where they run this entire length all the way up to the portal and Mt Whitney peak. Perhaps that's something to do while you're there (maybe not run it but visti both).

Las Vegas is great checkout http://www.las-vegas-nevada.com to find all the things you can do while in Vegas.