2506ft. Seems okay for Afan. While the hills are big, a lot of riding there is one big up, then lots of down. A spin round Whites at Afan according to my Strava logs clocks up 1700ft and I’ll be tired after that yet only about 11 miles. Though I find the descents are what gets me. At least it did back when they were rocky.
Yet a spin round the Surrey Hills round my way can get me into the 2500 to 3500ft range of climbing, yet the hills are much smaller. It’s just a lot more up and down but not one big long climb, so tends not to be so tiring. Though a long ride will be exhausting. Would have to be 25+ miles.
I have just come back of holiday in wales and while I was there went for a ride in the afan forest, I got totally lost but on my garmin shows I did 764 meters of going up hill, I have to say was quite tired the next day, the ride its self was 21 miles, had planned on about 14 but got very lost, so is 764 a fir bit or am I just unfit
If it’s any consolation the number of feet (or metres) climbed is a pretty poor indicator of the effort required off-road. If you are climbing on loose surfaces, for example or with lots of steps, rocks etc to negotiate and having to work hard on the descents too then a 21 mile ride with 764m of climbing could easily be an epic day out.