TBH, I've done enough 1000 mile days that I have lost count years ago, but I got too tired in the Elise after eleven-twelve hours. The non-op lumbar support bladder in the seat was one problem; the other was the mis-matched, worn out / aged out / unbalanced tires, and mediocre alignment, which just caused a lot of driver fatigue and a lot more NVH than is usual. I don't know how well I would handle a 'proper' Elise for the ~15-16 hours (incl gas etc) it takes to drive 1000 miles, but I applaud you for doing it.
With that said - most people aren't gonna be able to do that without a lot of complaints. Which is fair, honestly. The seats are hard, the position unusual, no cruise control, exceedingly little work to dampen NVH, etc. I don't think they're weenies for not enjoying driving an Elise 10+ hours a day, though I still think the complaints are overwrought.