we did two different 100 mile rides with some significant climbing ... apparently around 8K + elevation
rural areas - mostly farm country
those were my favs
we followed routes that at one time were used for organized rides ... (did those also) ... interestingly - 10 years ago or so ? - the organized rides altered the routes and dropped the major climbs
We did a lot of Angeles Crest Highway. I should go up there but car racers discovered it during covid.