We attended the winter Modernism Week in I think February 2017 (pre-retirement, so a business expense). Be prepared that you could have hot days and be sure to have a hat if you do the double decker bus tour (we were WARM at 85 degrees and so glad we weren’t on the bus the next day when it was over 90). No trip to Palm Springs is complete without a meal (or two) at Sherman’s Deli. I don’t know about reservations at “fancy” restaurants, but they do at least two Modernism weeks each year and of course winter is “high season” anyway, so it wouldn’t hurt to make them in advance if you have somewhere special you want to eat. If you want to tour Sunnylands, be aware tickets for tours of the Annenberg estate are available on the 15th of the previous month and sell out very quickly. And I wouldn’t be surprised if there are already Modernism events scheduled there so possibly access is not possible that week. I was ready to redecorate in hot pink, line green and bright yellow after the tour, it was well worth the price.