>>2742737The best way to tell how the culture is feeling is to look at Alltrails reviews for easy trails, where I have seen MANY people consider this elevation gain as difficult. This would be considered strenuous to many. I would say that real serious dayhiking generally starts to happen at the 15mi or 5000ft ele (25km, 1500m) mark and then ultrahiking is at around 25mi or 8000ft ele (40km, 2400m) in a day.
Also, the type of elevation gain and how you get it matters. Was this on a trail or bushwhacking? was it all concentrated in the first mile or was it gradual? Was it nice runnable switchbacks or Appalachian talus or scree or snow or ice or a tricky scramble.
For reference, I hike a lot and I usually ascend at around 1500ft/hr and maintain around 3mph on flat and between 2.5 and 2mph uphill, all dependent on terrain. The longest dayhike I've done was the Rim to Rim to Rim in the grand canyon which took me about 18 hours, and the hardest was bagging the 8 6000ft peaks in the northern smokies in a day.
The important thing is you actually got /out/ and put some miles on your feet, which is always commendable. What area of the US do you live in (I assume because you use ft and miles, and this looks like coastal California). I can recommend some really hard dayhikes and trails anywhere in the states if that's what you are looking for